Serological methods of laboratory diagnosis of syphilis. Express test for syphilis: advantages of diagnosis, indications, how to prepare and indications for conducting Express diagnosis of syphilis

Syphilis is multifaceted. The infection, entering the body, leaves marks not only on the skin and genitals, but also destroys the nervous system, musculoskeletal system, lungs, impairs hearing and vision. Despite a wide range of symptoms and variants of their combinations, doctors have learned to identify the disease and accurately indicate the stage of its development.

Society wants to protect itself from infection with Treponema pallidum. Therefore, a number of express tests are provided for the early diagnosis of syphilis or the identification of carriers of the infection. The rule was blood sampling for laboratory diagnostics:

• in cases of pregnancy;
• before the operation;
• from donors before donating blood or organs for transplantation;
• medical workers, teachers, educators, catering workers, etc.;
• military personnel;
• at the prisoners.

Laboratory test and clinical examination for syphilis will be carried out for:

• patients with signs of STDs;
• sexual partners and other family members of a person diagnosed with syphilis;
• babies born from a sick mother;
• anyone diagnosed with another sexually transmitted disease;
• testing the effectiveness of the therapeutic method during treatment;
• everyone who has tested positive.

The procedure for detecting infection at a venereologist's appointment

From a conversation with a patient, the doctor finds out:

• whether the partner has a confirmed diagnosis of syphilis;
• whether there have been rashes on the genitals before;
• Are the lymph nodes inflamed?
• did it take place unprotected sex 3-4 weeks ago.

During a clinical examination of the skin, genitals, anus, mucous membranes, the specialist finds out the similarity of rashes and other skin lesions with those characteristic of syphilis. Peripheral lymph nodes are carefully palpated to assess the degree of their enlargement.

In cases of syphilides (hard chancre, roseol, papules, granulomas), the doctor prescribes a histomorphological examination. The laboratory describes appearance and study the content of education. Based on the results, the stage of the disease is judged.

A decisive contribution to the diagnosis of syphilis is made by the laboratory method of identifying the pathogen or traces of the immune response to infection.

The diagnosis is established on the basis of a combination of data obtained after a clinical examination and laboratory tests. In exceptional cases, when it is impossible to conduct tests, treatment is prescribed on the basis of an examination.

Diagnosis of complications

Secondary and tertiary syphilis can produce complications called specific visceritis. All organs and systems can be included in the process, but most often venereologists observe lesions:

• liver;
• nervous system;
• bones;
• hearts.

Syphilis is especially dangerous for pregnant women. In addition to complicated pregnancy, intrauterine or vertical (in the birth canal) infection of the fetus, stillbirth is not excluded.

It is important to diagnose not only the infection, but also secondary diseases in time. For this purpose, in addition to specific tests and general urine and blood tests, additional examinations are carried out (Table).

Laboratory analyzes of biological materials

Laboratory diagnosis of syphilis began to develop since 1905, when the causative agent of the disease, pale treponema, was discovered. Prior to this, rabbits were infected with the contents of syphilides, which are 100% susceptible to infection. Already in 1906, Wasserman developed the first serological test for syphilis (RW). In 1949, medicine proposed a more specific treponema pallidum immobilization test (TPT), but RW has not been ousted from laboratories until today.

The first analyzes are being replaced by modern diagnostic methods. They differ in technique and purpose. In the list of current tests:

• dark-field microscopy - involves the study of a smear or scraping to detect treponema in the substrate under study (in everyday life, this study is sometimes called a "smear for syphilis");
• molecular biological methods for detecting specific DNA (polymerase chain reaction, DNA probing);
• serological diagnosis of syphilis in blood serum or cerebrospinal fluid.

Dark field microscopy

Samples are taken from the lesions for microscopic examination for pale treponema. The objects of testing are:

• contents of syphilis;
• tissue fluid;
• liquor;
• amniotic fluid;
• cord tissue.

Treponema has received the characteristic "pale" due to its resistance to the action of most dyes. A living microbe is clearly visible in a dark field with special illumination. The laboratory assistant pays attention to the morphological features of bacteria and observes the nature of their movement.

For histomorphological examination, samples are stained with silver (according to Morozov) or according to Romanovsky-Giemsa.

Direct microscopy methods are used to diagnose congenital disease or advanced stages of syphilis. You can check its correctness by direct immunofluorescence reaction (RIF-Tr) or polymerase chain reaction (PCR). In the first case, anti-treponemal antibodies and a fluorescent dye help to identify the pathogen, and in the second case, DNA molecules of pale treponema.

Search for pathogen DNA

Even a single treponema DNA molecule can be detected in a blood test. Advances in this field have been made possible since 1991, when the polymerase chain reaction (PCR) test was invented. The carrier of hereditary information is propagated under special temperature conditions and is repeatedly copied by an enzyme - DNA polymerase. After, by electrophoresis, the desired fragments of the chain are revealed.

This is a very accurate and specific test. Abroad, it has become the gold standard for diagnosing syphilis. In Russia, PCR is still more research than clinical.

Another way to detect treponema by DNA probing (hybridization nucleic acids). In this case, the denatured DNA is connected to a specific probe. A change in the color of the filter on which the samples are applied indicates contamination.

Serological diagnostic methods

Serological non-treponemal and treponemal tests can be used for various diagnostic purposes. During the analysis, antibodies to pale treponema in the blood are detected.

As an express diagnostic or screening, it is recommended to refer to the following non-treponemal tests:

• RPR - Rapid Plasma Reagins test;
• RST, Reagin Screen Test;
• TRUST - test with toluidine red and unheated serum (Toluidin Red Unheated Serum Test);
• USR - test for the determination of active plasma reagins (Unheated Serum Reagins);
• VDRL – study laboratories sexually transmitted diseases(Venereal Disease Research Laboratory);
• precipitation microreactions (MRP) with plasma or inactivated serum;
• complement fixation reaction (RSK) and its variants with cardiolipin antigen (RSKk).

The method is based on the search for antibodies (IgM and IgG) to the lipids of damaged cells and lipoproteins of pathogen membranes. The above tests show a positive answer already a week after the appearance of the first syphilides.

Antibodies to treponema itself are detected by methods:

• ELISA - enzyme immunoassay - ELISA (Enzymelynked immunosorbent assay);
• FTA - immunofluorescence reactions - RIF (Fluorescent treponemal antibody);
• RW - complement fixation reactions (Wassermann reaction);
• RW with treponemal antigen - RSKt;
• TPHA - reactions of passive hemagglutination - TPHA (Treponema pallidum haemagglutination assay);
• TPI - reactions of immobilization of pale treponema - RIBT or RIT (Treponema pallidum immobilization test);
• Western Blot - immunoblotting.

Venereologists follow a specific procedure for conducting serological tests. As an express diagnostic, one of the non-treponemal tests is performed. Low sensitivity in the early and late stages of infection is taken into account. Therefore, both negative and positive responses with a certain clinical picture should be rechecked by treponemal methods.

In different life situations, combinations of positive and negative answers can be observed. The table will help decipher them.

The final conclusions are made by the venereologist on the basis of a set of data: the clinical picture, histological and laboratory studies.

Sources:

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2. Dmitriev G.A., Frigo N.V. // Syphilis. Differential clinical and laboratory diagnosis. – M.: Med. book, 2004. - S. 26-45.
3. Loseva O.K., Lovenetsky A.N. Epidemiology, clinic, diagnosis and treatment of syphilis: a guide for doctors. - M., 2000.
4. Pankratov V.G., Pankratov O.V., Navrotsky A.L. etc. // Recipe (Appendix: International Scientific and Practical Conf. "Modern Approaches to the Diagnosis, Treatment and Prevention of Sexually Transmitted Infections", Grodno, 2005). - 2005. - S. 165-169.
5. Pankratov V.G., Pankratov O.V. // Modern possibilities of laboratory diagnostics of syphilis and interpretation of research results. – Minsk, Belarusian Medical Academy of Postgraduate Education, 2006.
6. Pankratov V.G., Pankratov O.V., Krukovich A.A. etc. // Healthcare. - 2006. - No. 6. - P. 35-39.
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8. Jurado R.L. // STD. - 1997. - No. 3. - S. 3-10.
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10. Romanowski B., Sutherland R., Flick G.H. et al. // Ann. Med. –1991. - V. 114. - P. 1005-1009.

The content of the article

Laboratory diagnosis of syphilis

Significant changes have taken place in the laboratory diagnosis of syphilis in the last decade. Such classical tests as the complement fixation reaction (Wassermann reaction), Kahn reaction, cytocholic and other precipitation reactions have lost their relevance due to insufficient sensitivity and a large number of non-specific results. Instead, many times more sensitive and specific tests are used. Molecular biological DNA and RNA tests have been introduced. When interpreting the test results, computer analysis is used, which excludes their subjective assessment. Testing is automated, methods are standardized, various diagnostic systems have been developed and certified. This opens up a wide range of diagnostic possibilities. the most difficult cases diseases. In the diagnosis of syphilis are used:
1. Bacterioscopy.
2. Methods of serological research (non-specific and specific).
3. Study of cerebrospinal fluid (CSF).
4. Histological examination - mainly in the stage of tertiary syphilis.
5. Bacterioscopic examination.
6. Microscopic examination of the native preparation of discharge of erosive or ulcerative rashes or punctate from the lymph node to detect Treponema pallidum.

Bacterioscopic method

Obtaining material and preparing for the study
The material from the mucous membranes, the skin of the genital organs or the extragenital area with suspicious erosive or ulcerative defects, directly from the surface of the hard chancre, wide condyloma, erosive papules, is received by a laboratory doctor or any other doctor in a room where a microscope with a dark field of view is prepared. The surface of ulcus durum or erosive papules is wiped with a swab dipped in saline, and then irritated with a bacteriological platinum or tungsten loop for several minutes, until a clear tissue fluid appears from the deep layers. It is necessary to ensure that blood is not mixed with it, otherwise it will complicate the study. The resulting liquid is transferred by a loop to a glass slide, where, if necessary, saline can be added. The prepared preparation is examined in the dark field of the microscope. If the result is negative, the study is repeated for several days in a row, and in the intervals between studies, applications with saline are applied.
Do not use antibiotics and local antiseptics before microscopic examination!
Study
The resulting material with a drop of saline, placed on a glass slide and covered with a cover slip, is examined under a microscope using a 40x objective and a 10x eyepiece. For microscopic confirmation of the diagnosis, it is necessary to detect at least 2-3 morphologically typical, live treponemas with characteristic movements. A negative result does not exclude the possibility of syphilis, so the study must be repeated several times. The patient's use of antibiotics or topical antiseptics is an important history.
Clinical Significance
The diagnosis of primary seronegative syphilis can only be confirmed in the presence of pale treponema. In patients with acquired or congenital syphilis, treponemas are found in all syphilides of both early and late syphilis. The intensity of the tissue reaction is inversely proportional to the number of these microorganisms, the largest number of which is found in primary syphiloma (hard chancre), in regional lymph nodes and papules of secondary fresh syphilis, and the smallest in late syphilides. In patients with secondary syphilis, pale treponemas can be found in all organs.
In the circulating blood, treponemas can be present for a short time only in patients with secondary fresh syphilis and early congenital syphilis. Blood is an unfavorable environment for treponemas, which they quickly leave, migrating into tissues. It is extremely difficult to detect treponema in the cerebrospinal fluid, even in patients with tabes dorsalis and progressive paralysis. Human sperm is infectious. Urine, sweat, saliva are not contagious unless they come into contact with weeping eruptions. On the contrary, treponemas are found in mother's milk. In patients with syphilis, treponema can be detected in the punctate of the lymph nodes, in the spleen and in nonspecific lesions (in the exudate of abdominal elements of various origins, for example, in the vesicles of herpes simplex). The method is characterized by low cost, the answer can be obtained within half an hour.
Possible mistakes
For a quick diagnosis of syphilis, it is important that the patient does not self-medicate. If the surface of the chancre, warts or erosive papule is covered with a crust formed as a result of secondary infection, it should be cleaned with saline.
Irritation of the surface of the element in order to obtain tissue fluid must be performed very carefully so as not to cause bleeding, since the presence of erythrocytes in the micropreparation makes it difficult to diagnose qualitatively. The study is considered positive only if morphologically typical treponemas are found with the presence of at least 8 whorls and characteristic movements. Treponema pallidum must be differentiated from T. refringens, T. balantidis, T. phagadenis, T. gracilis, T. macrodentinum, T. microdentinim.

Serodiagnosis of syphilis

In identifying and confirming the diagnosis of syphilis, especially in the case of late and latent forms of the disease, when clinical manifestations are negligible or absent, serological diagnostic methods are of decisive importance. There have been cases when only specific positive test results obtained in the study of serum or plasma testify to the disease of syphilis.

Non-specific (non-treponemal) tests

Nonspecific (non-treponemal) tests, which are methods for rapid diagnosis of syphilis, include RPR (Rapid Plasma Reagins), an inactivated serum test - MRP (precipitation microreaction with cardiolipin antigen) and their modifications. These are the so-called flocculation tests, where the “antigen + antibody” complex formed during the reaction forms flakes that are distinguishable with a magnifying glass. In all these tests, the cardiolipin antigen obtained from the heart muscle of a bull is used as an antigen and has no connection with the antigens of the causative agent of syphilis Treponema pallidum.
In the diagnosis of syphilis, non-treponemal tests are used as screening tests and are not suitable for confirming the diagnosis of syphilis. Such tests are used to examine large groups of the population during preventive examinations or in an epidemiologically unfavorable situation. The tests are quite sensitive, technically simple, but require specially trained personnel. Test results must be evaluated and confirmed by a physician. For express diagnostics, mainly serological tests MCI and RPR are used. The sensitivity of non-treponemal tests for early forms of syphilis is approximately 70%, for secondary syphilis - 100%, for latent forms - 30%. Non-specific tests can give false positive results in 2-2.8% of cases. In certain categories of patients, for example, in pregnant women, this number can increase to 3-3.5%. MCI and RPR become positive 1-4 weeks after the appearance of the chancre, that is, 1-1.5 months after infection. In about 2% of cases, the so-called “prozone” phenomenon is observed, when, against the background of a pronounced clinical picture of syphilis and positive results of specific serological reactions, RPR may not give positive results. In such cases, a positive result is obtained by diluting the serum sample. When examining pregnant women, donors, patients of the otolaryngological, neurological and neuropsychiatric departments, non-treponemal tests are necessarily used in combination with a specific diagnostic test (RPHA, ELISA).
Quantitative methods (determination of antibody titer) MRP and RPR are used to monitor the effectiveness of treatment.
MCI principle
When an emulsion of a cardiolipin antigen is combined with the plasma or serum of a patient with syphilis, a flocculate (antigen + antibody complex) is formed, which looks like white snowflakes. Each of the test systems (MRP, RPR) has its own technical features, but the principle of the method is the same.
Test material Plasma or serum used for analysis must be transparent. Chylous or hemolyzed material is not suitable for testing.
- Obtaining plasma from capillary blood: blood is taken from a finger in the same way as the method
definitions of ESR. A 5% solution of sodium citrate is drawn into the Panchenko pipette to the “K” mark, and then poured back into the bottle to the “25” mark on the pipette. The remaining sodium citrate is poured into a centrifuge tube, where add three pipettes of blood from the patient's finger, dialed up to the "K" mark, and mix. The blood is left at room temperature until the separation of plasma and red blood cells. To speed up the process, the blood can be centrifuged. The resulting plasma is taken with a Pasteur pipette or a special pipette and used for diagnosis. To obtain plasma, it is recommended to use special microvets. The material must be delivered to the laboratory within 4-6 hours.
- Obtaining inactivated serum: serum is collected either by separating it from the clot during blood settling, or by centrifuging sterile blood taken from a vein. Serum can be stored in the refrigerator at 4°C for up to 5 days. In the laboratory, the resulting serum is inactivated at a temperature of +56°C for 30 minutes. Testing is performed on transparent recessed polystyrene plates (MPP) or on special cardboard plates (RPR).
Evaluation of results
The results of MCI are read in transmitted light on a black base or over a light source with the naked eye or with a magnifying glass. In the recesses where the plasma or serum of a patient with syphilis is located, white flakes of various sizes are formed in various quantities. If large flakes or their conglomerates are noted in the recess, and the surrounding liquid becomes transparent, the result is considered positive (4+, 3+). Small flakes - the result is weakly positive (2+, 1+). In the negative case, flakes are not formed (negative). In doubtful cases (+-) should be guided by the "negative control". If no flakes form in the negative control well, the result is rated as doubtful (+-). The study continues with a quantitative method, by diluting the serum, since it is necessary to exclude the so-called “prozone” phenomenon, when no precipitate forms in an undiluted plasma or serum sample, and flakes appear when it is diluted.
For the RPR test, ready-to-use certified reagin complexes are used.
The quantitative method MRP, RPR is used to determine the amount of antibodies in a sample of the studied serum during and after treatment.
Possible mistakes
Incorrect taking of blood from a finger - there are bubbles in the capillary, the mark on the capillary is inaccurately fixed.
1. There is no control serum in the reaction (also weakly positive).
2. In the finished emulsion, an uneven concentration of antigen due to insufficient mixing before use.
3. Bacterial infection of the working solution.
4. Failure to comply with the rules for the storage and manufacture of plasma, serum, antigens and their working solution.
5. Use of divalent sodium citrate instead of trivalent.
6. Violation of the rules for the use of glassware, pipettes, non-compliance with the procedure for the study.
Failure to follow these rules can give both false negative and false positive results.

Specific (treponemal) tests

With the help of specific tests in the serum of a patient with syphilis, antibodies formed in the body to specific antigens of Treponema pallidum are detected. Treponemal tests are used to make and confirm the diagnosis, as well as in the differential diagnosis. Specific tests are characterized by high sensitivity and highly specific results. The mechanisms of specific tests are not the same, they can detect different antibodies, so the indications for their use vary. When prescribing these studies, the doctor must understand the essence of each test, be able to justify his choice, navigate in a variety of tests in order to choose the best option for making a diagnosis and appropriate treatment, and also draw a conclusion about its results.
The most commonly used treponemal tests are TPHA and IFA.

Passive hemagglutination reaction (RPHA, TRHA)

Method principle
Syphilis TPHA-Test (Treponema pallidum haemagglutination test) is an indirect hemagglutination test that is used to detect specific antibodies to Treponema pallidum. Sheep or rooster erythrocytes are sensitized by Treponema pallidum antigen. In the presence of antibodies, agglutination of sensitized cells occurs - specific patterns are formed in the microwells. The cell suspension also contains Reiter's treponemal extract, which absorbs non-pathogenic treponemal antibodies.
Material under study
Only serum is tested. Hemolyzed and cloudy samples are not suitable. Samples can be stored for 24 hours at +2 to + 8°C, or up to 4 weeks at -20°C.
Characteristics of the RPHA method is a good diagnostic test, however, positive results must be confirmed using some other specific test for the diagnosis of syphilis. In the case of cured syphilis, the results of RPHA can remain positive for a long time. False positive results are observed in the case of leprosy, infectious mononucleosis, as well as in the case of connective tissue diseases. Results are read in 45-60 minutes.
Interpretation of results
The results are evaluated according to the "4+" system. - A negative result is defined when a clear and distinct dot of non-agglutinated cells forms in the center of the test well with or without a very small gap in the center. A doubtful result is determined when, instead of a small lumen, a ring of small density appears on a transparent background in the center of a dot of non-agglutinated cells. Such samples must be carefully rechecked (+/-, "1+" - doubtful). A positive result is determined when the cells agglutinate, forming a clearing-like area around which a ring forms. Depending on its value, the result of the reaction is estimated as "2+", "3+" or "4+", respectively.
If a point of non-agglutinating cells is observed in the control well of the test, this means that the serum is suitable for testing.
If a reaction occurs in the control well of the test, this means that the test sample contains non-specific agglutinins. Serum is not suitable for testing and must be carefully processed.

Quantitative RPHA method

To control the effectiveness of treatment, you can use the quantitative method of RPGA - the determination of antibody titer. Titration is recommended for strongly positive samples, which are rated as "4+", since the result "4+" occurs if the sample titer is > 1:80.
Interpretation of results
If hemagglutination does not occur in the control well, then the observed hemagglutination in the test wells indicates that the sample is positive. The titer is determined by the last dilution, which indicates the result<4+»:
1. dilution in the hole 1:80
2. dilution in the hole 1:160
3. dilution in the well 1:320, etc. It is not necessary to titrate the results "3+" or "2+".
For the study of each sample, it is also necessary to use positive and negative control sera of TPHA. Negative control serum always shows a pronounced dot, positive control serum - hemagglutination "4+".
RPHA is characterized by high sensitivity, with its help it is possible to detect a very small amount of antibodies in the serum. The test after treatment is negative very slowly, it can show weakly positive results for many years after recovery.

ELISA tests - ELISA

The test belongs to enzyme immunoassays, which have recently been widely used in the world for the diagnosis of various infectious diseases. In the diagnosis of syphilis, ELISA began to be introduced in the 80s, when diagnostic tests were developed and certified and the testing methodology was standardized.
The test is based on the indirect Koons method. Specific antibodies are found in the patient's serum. The sensitivity and specificity of the test is comparable to immunofluorescent tests. An ELISA test can detect antibodies of all essential classes (IgM, IgA, IgG). The ELISA test is especially valuable in the early diagnosis of syphilis, since it becomes positive already at the end of the incubation period. The ELISA test is an ideal diagnostic method suitable for the simultaneous examination of a large number of samples. It is recommended to use it when examining pregnant women, contact persons, donors and representatives of risk groups. ELISA is also used as a confirmatory test for samples showing positive results using various non-specific tests and TPHA.
The serological diagnosis of syphilis is hampered by the presence of rheumatoid factor, other antibodies, and cross-reactions with other related bacteria such as Treponema phagedenis and Borrelia burgdorferi in the blood. When using the ELISA test, these factors practically do not affect the results. High lipid concentration, hemolysis of the sample are not barriers to testing, as is the case with most other tests.
The ELISA test allows you to determine all significant classes of antibodies and shows a high degree of sensitivity at all stages of the disease (test sensitivity 97-98%, specificity - 98.5-99%). A negative ELISA result excludes syphilitic infection with a high degree of probability. In recent years, test systems have been created to determine individual classes of antitreponemal antibodies IgM-ELISA, IgG-ELISA. ELISA can remain positive for many years even in treated patients, therefore it is not used as a criterion for recovery. In ELISA tests, the “prozone” phenomenon, which gives false negative results with other testing methods, is not observed, since the titer of specific antibodies is very high.
Method principle
1. AG is deposited on the wells of polystyrene
tablet.
2. The test serum is added, the "AG + AT" complex is formed.
3. Enzyme-labeled antibodies to human immunoglobulins are added.
4. A color-changing substrate is added and the activity of the enzyme is determined from the intensity of the color. The color of the solution depends on the amount of antibodies in the test sample.
With this method, IgG and IgM antibodies can be detected together, as well as antibodies of the IgM class separately. The results are regarded as "positive" or "negative".

Tests Confirming the Diagnosis of Syphilis

Immunofluorescent tests - RIF (FTA)
This group includes: RIF-200, RIF-abs (FTA-abc), IgM RIF abs (IgM FTA-abc), RIF liquid.
Since the 1960s, sensitive and specific immunofluorescent tests have been widely used to confirm and differentially diagnose syphilis. The immunofluorescein antibodies detected by these tests are the first to appear in serum, so the test becomes positive by the end of the first week after infection. This allows you to diagnose syphilis when other tests (except for ELISA) remain negative. RIF-abs in primary seronegative syphilis is positive in 87% of cases at the end of the second and beginning of the third week after the onset of the primary affect. To reduce the number of false positive results (RIF-abs - 2.8-3%), it is recommended to use a complex of reactions - RIF-abs + RIF-200. False positive results with RIF-200 are observed in approximately 2% of cases. In the case of secondary syphilis, RIF-abs is positive in 100%, in the case of a late form of the disease - in 92-100%, in the case of a specific lesion of internal organs - in 94-100%. Even after treatment of syphilis, RIF-abs gives positive results for a very long time, therefore it is not used to determine the effectiveness of treatment, unless a quantitative method of RIF-abs is used - determination of antibody titer.
In recent years, the IgM RIF-abs reaction has been increasingly used. In the patient's serum, IgM antibodies appear before the others. This test is used in early diagnosis, in the examination of contacts, to monitor the effectiveness of treatment, in the differential diagnosis of relapse and reinfection, as well as in the case of congenital syphilis or to determine the presence of maternal antibodies in newborns.
As you know, due to the large molecular weight of IgM antibodies do not penetrate the placental barrier. In the blood of the mother (patient with syphilis), predominantly IgG antibodies circulate, for which the placental barrier is not an obstacle, and which enter the bloodstream of the child. In the presence of newborn IgM antibodies in the serum, one should think about infection with syphilis. There is still no consensus in the world about the duration of the circulation of IgM antibodies in the patient's serum. Most authors believe that they reach their maximum at 6-9 weeks, and are not detected after 18 months of age. The German scientist Miller suggests that IgM circulate until the disappearance of clinical symptoms, O "Neal - that IgM circulate in the blood for up to 5 years. According to Miller, in 60% of cases of Syphilis lateens praecox IgM is no longer detected in serum. If treatment starts early, IgM disappear within 5-6 months, if treatment starts later - they persist for 1-2 years.Some authors use the reaction of IgM RIF-abs as a criterion of cure.
Method principle
The test serum is incubated with Treponema pallidum (antigen), which is fixed on a glass slide. In the case of a positive result, an antibody + antigen complex is formed associated with fluorescein-treated antibodies to human globulins. Before testing, the test serum is treated with a sorbent (non-pathogenic extract of Treponema Reiteri) to exclude the binding reaction of non-specific antibodies.
The result is a glow of immune complexes of varying intensity, which is determined using a fluorescent microscope.
Evaluation of results
The study is performed using a fluorescent microscope (a mercury-quartz lamp with an immersion system, an eyepiece with 4 or 5x magnification, filters depending on the brand of microscope). results
are evaluated by the intensity of the luminescence of immune complexes.
Preparations that give a glow of 4+, 3+, 2+ are positively evaluated. Yellow-green luminescence is rated as 4+, bright green glow - 3+, pale green glow - 2+. If the intensity of the luminescence is 1+, the reaction is considered negative (background staining is observed in the preparation or there is no staining - only shadows are determined). The result of "2+" must be monitored using other specific tests.

Treponema pallidum immobilization reaction - RIBT

This test for the diagnosis of syphilis was developed in 1949 and proposed to be used by R. Nelson and M. Mayer. Even today, this test is considered the most effective in diagnosing syphilis and serves as a benchmark in the most difficult cases. RIBT practically does not give false positive results. As an antigen, a suspension of live, virulent treponemas obtained from rabbit testicles 7-9 days after intratesticular infection is used. The test is technically complex, requires specially trained personnel and is carried out only in specialized laboratories. The method is based on a phenomenon in which the formed “antigen + antibody” complex is fixed on treponemas, making them immobile. It must be remembered that immobilisin antibodies appear in the patient's serum relatively late, therefore, with primary and secondary fresh syphilis, the test is weakly positive or negative. However, it is indispensable in the diagnosis of latent forms of syphilis, syphilis of internal organs, neurosyphilis. After therapy, the test negatives slowly and is therefore not used to assess the effectiveness of treatment. The test can remain positive for many years after completion of therapy, and therefore is used for the retrospective diagnosis of syphilis.
Obtaining and processing the study serum
Before setting RIBT, the examined patient is forbidden to use antibiotics. After the use of bicillin, blood for research on RIBT is taken no earlier than a month later.
Blood is taken from a vein on an empty stomach into a sterile, dry, chemically clean test tube or vacutainer. Serum must be separated from the clot under sterile conditions no later than 24 hours after blood sampling. Before the study, the serum should be inactivated at a temperature of 56 ° C for 30 minutes. If the same serum needs to be re-examined, it is inactivated at 56°C for 15 minutes.
Serum can be stored in the refrigerator at 10°C for up to 15 days. Adding any preservatives to the whey is unacceptable!
All utensils used for the reaction (pipettes, test tubes, vials, etc.) must be sterile. Testing is carried out in a sterile box.
Interpretation of results
In the dark field of view of the microscope, the number of immobile treponemas in the test and control preparations is determined, expressing the number of immobile treponemas as a percentage.
RIBT is considered negative if immobilization is 0-20%; doubtful - at 21-30%, weakly positive - at 31-50% and positive if immobilization exceeds 50%. Serums that give a questionable or weakly positive result are recommended to be re-examined. It is also desirable to repeat the study in cases where the obtained results of RIBT completely do not coincide with the results of other standard tests for the diagnosis of syphilis. Such test sera deserve special attention, since the results of RIBT are different in confirming or excluding the diagnosis of syphilis.

Treatment of syphilis

Duration of treatment and applied methods
at different stages of syphilis are different.
Schemes of treatment of patients with syphilis in different periods:

Preventive treatment

- Benzathine benzylpenicillin G or Bicillin-1 2.4 million units IM once or
- Bicillin-3, 1.8 million U or Bicillin-5, 1.5 million U / m twice a week No. 2 or Benzylpenicillin novocaine salt, 600 thousand U / m twice a day, daily for 7 days or
Procaine benzylpenicillin 1.2 million U/m once a day daily No. 7 or Benzylpenicillin sodium salt crystalline 1 million U/m every 6 hours (4 times a day) daily for 7 days.

Treatment of patients with primary syphilis

- Benzathine benzylpenicillin G 2.4 million IU IM once every 7 days No. 2 or
- Bicillin-1, 2.4 million U / m once every 5 days No. 3 or
- Bicillin-3 1.8 million units or Bicillin-5 1.5 million units intramuscularly twice a week No. 5 or
- Procaine benzylpenicillin 1.2 million IU IM once a day daily No. 10 or
- Benzylpenicillin novocaine salt 600,000 IU intramuscularly twice daily for 10 days or
- Benzylpenicillin sodium salt crystalline, 1 million IU / m every 6 hours (4 times a day) daily for 10 days.

Treatment of patients with secondary and early latent syphilis

- Benzathine benzylpenicillin G 2.4 million U/m once every 7 days No. 3 or Bicillin-1 2.4 million U/m once every 5 days No. 6 or
Bicillin-3 1.8 million units or Bicillin-5 1.5 million units intramuscularly twice a week No. 10 or Procaine benzylpenicillin 1.2 million units intramuscularly once a day daily No. 20 or Benzylpenicillin novocaine salt 600 thousand units IM twice a day daily for 20 days or
Benzylpenicillin sodium salt crystalline, 1 million U / m every 6 hours (4 times a day) daily for 20 days. In patients with a disease duration of more than 6 months, it is recommended to use benzylpenicillin novocaine salt, procaine benzylpenicillin or benzylpenicillin sodium crystalline salt.

Treatment of patients with tertiary, latent latent and latent unspecified syphilis

Benzylpenicillin sodium salt crystalline 1 million U / m every 6 hours (4 times a day) daily for 28 days, two weeks later - the second course of treatment of benzylpenicillin sodium salt crystalline in similar doses or one of the drugs of medium duration (benzylpenicillin novocaine salt, procaine benzylpenicillin) for 14 days or
Procaine benzylpenicillin 1.2 million U/m once a day daily No. 20, two weeks later - the second course of procaine benzylpenicillin in a similar dose No. 10 or Benzylpenicillin novocaine salt 600 thousand U/m twice a day daily within 28 days, after 2 weeks - the second course of benzylpenicillin novocaine salt in the same dose for 14 days.

Treatment of patients with damage to internal organs and the musculoskeletal system

Treatment of patients with visceral syphilis is recommended to be carried out in a hospital - dermatovenerological or therapeutic, taking into account the severity of the lesion. Treatment is carried out by a dermatovenereologist together with a therapist who prescribes concomitant and symptomatic therapy.
Treatment of patients with early visceral syphilis
- Benzylpenicillin sodium salt crystalline 1 million U / m every 6 hours (4 times a day) daily for 20 days or
- Benzylpenicillin novocaine salt 600,000 IU intramuscularly twice daily for 20 days or
Procaine benzylpenicillin, 1.2 million units IM once a day, daily No. 20.
Treatment of patients with late visceral syphilis
Treatment begins with a two-week preparation with broad-spectrum antibiotics (tetracycline, erythromycin, doxycycline). Then they move on to penicillin therapy.
- Benzylpenicillin sodium salt crystalline 400 thousand U / m every 3 hours (8 times a day) daily for 28 days, after 2 weeks - the second course of benzylpenicillin sodium salt crystalline in the same dose for 14 days or
- Benzylpenicillin novocaine salt 600 thousand U / m twice a day daily for 28 days, after 2 weeks - the second course of benzylpenicillin novocaine salt in the same dose for 14 days or
- Procaine benzylpenicillin, 1.2 million U / m once a day, daily for 28 days, after 2 weeks - the second course of procaine benzylpenicillin in the same dose for 14 days.

Treatment of patients with neurosyphilis

Treatment of patients with early neurosyphilis
- Benzylpenicillin sodium salt crystalline, 10 million IU intravenously twice a day, daily for 14 days. A single dose of an antibiotic is diluted in 400 ml of isotonic sodium chloride solution and injected intravenously over 1.5-2 hours (solutions are used immediately after preparation) or
Benzylpenicillin sodium salt, crystalline, 2-4 million IU intravenously 6 times a day daily (daily dose 12-24 million IU) for 14 days. A single dose of the antibiotic is diluted in 10 ml of isotonic sodium chloride solution and injected slowly over 3-5 minutes into the cubital vein.
To prevent an exacerbation reaction (in the form of the appearance or aggravation of neurological symptoms) in the first 3 days of penicillin therapy, prednisolone can be taken at a daily dose of 50-60 mg (once in the morning).
6 months after the end of treatment, a control study of the cerebrospinal fluid is performed. In the absence of its sanitation, the course of treatment is recommended to be repeated.
Treatment of patients with late neurosyphilis
Treatment of patients with late neurosyphilis (progressive paralysis, spinal tabes) is carried out according to the same methods that are recommended for the treatment of patients with early neurosyphilis. The difference consists in conducting two courses of treatment instead of one, followed by CSF control after 6 months. In the absence of sanitation of the cerebrospinal fluid, another course of treatment is carried out.
With progressive paralysis and dorsal tabes, the best effect of therapy, as a rule, is the absence of disease progression.
- Crystalline benzylpenicillin sodium salt, 10 million units IV drip twice a day, daily for 14 days, two weeks later - a second course of crystalline benzylpenicillin sodium salt in a similar dose for 14 days or
- Crystalline benzylpenicillin sodium salt, 2-4 million units i.v. bolus 6 times a day, daily for 14 days, after 2 weeks - the second course of crystallized benzylpenicillin sodium salt in the same dose for 14 days. In patients with progressive paralysis, the use of prednisolone is indicated at the beginning of therapy to prevent the exacerbation of psychotic symptoms against the background of specific treatment.

Treatment of syphilis in case of intolerance to penicillin preparations

In the presence of allergic reactions to penicillin, reserve drugs are used:
- Doxycycline 0.1 g per os 2 times a day daily for 10 days for preventive treatment, 15 days for the treatment of primary and 30 days for the treatment of secondary and early latent syphilis or
- Tetracycline 0.5 g per os 4 times a day daily for 10 days for preventive treatment, 15 days for the treatment of primary and 30 days for the treatment of secondary and early latent syphilis or
- Erythromycin 0.5 g per os 4 times a day daily for 10 days for preventive treatment, 15 days for the treatment of primary and 30 days for the treatment of secondary and early latent syphilis or
- Oxacillin sodium salt or ampicillin sodium salt, 1 million U / m 4 times a day (every 6 hours) daily for 10 days for preventive treatment, 14 days for primary treatment and 28 days for secondary and early latent treatment syphilis or
- Ceftriaxone 0.5 g / m once a day daily No. 5 for preventive treatment and No. 10 for the treatment of primary syphilis; 1.0 g / m once a day daily No. 20 for the treatment of secondary and early latent syphilis.

Treatment of neurosyphilis in case of intolerance to penicillin preparations

One of the preferred reserve drugs for neurosyphilis is doxycycline, which is administered orally at 0.1 g 3 times a day.
Tetracycline and erythromycin are not recommended for neurosyphilis, as they do not penetrate the blood-brain barrier well.
Semi-synthetic penicillins - oxacillin or ampicillin - are administered intramuscularly at 1 million units per injection (the dose is diluted in 5-6 ml of distilled water) 4 times a day. Duration of treatment - 28 days.
Ceftriaxone penetrates well into organs, tissues and body fluids, in particular - into the spinal cord. In addition, it has a high treponemicidal activity. In early neurosyphilis, ceftriaxone is prescribed 1.0-2.0 g IM once a day, daily for 20 days. In severe cases (syphilitic meningoencephalitis, acute generalized meningitis), intravenous use of the drug and an increase in the daily dose to 4.0 are possible. For the treatment of late forms of neurosyphilis, ceftriaxone is prescribed 1.0 g / m once a day, daily for 20 days, after 2 weeks - the second course of the drug in the same dose daily for 10 days.

Additional Treatment

Additional treatment is indicated if:
- a year after the full treatment of early forms of syphilis, there was no 4-fold decrease in MP titer (RPR);
- there is a delayed negative serological response over a period of two years without a tendency to further decrease in titers/test positivity, or
- clinical/serological recurrence. It is carried out once or twice. Preferred use: Crystalline benzylpenicillin sodium salt, 1 million units IM every 4 hours (6 times a day) daily for 20 days or
- Ceftriaxone 1.0 g / m once a day, daily for 20 days.

Treatment of children

Specific treatment of children with early congenital syphilis
- Benzylpenicillin sodium salt crystalline at the rate of 100 thousand units / kg of body weight per day / m, divided into 6 injections (every 4 hours), daily for 14 days or
- Procaine benzylpenicillin at the rate of 50 thousand units / kg of body weight per day / m once a day daily for 14 days or
- Benzylpenicillin novocaine salt at the rate of 50 thousand units / kg of body weight per day / m, divided into two injections (every 12 hours), daily for 14 days.
Specific treatment of children with late congenital syphilis
Benzylpenicillin sodium salt crystalline at the rate of 50 thousand units / kg of mass
bodies per day in / m, divided into 6 injections (every 4 hours), daily for 28 days; two weeks later - the second course of benzylpenicillin sodium crystalline salt in a similar dose for 14 days or
- Procaine benzylpenicillin at the rate of 50 thousand units / kg of body weight per day / m once a day, daily for 28 days, after two weeks - a second course of procaine benzylpenicillin at the same dose for 14 days or
- Benzylpenicillin novocaine salt at the rate of 50 thousand units / kg of body weight per day / m, divided into two injections (every 12 hours), for 28 days; two weeks later - the second course of benzylpenicillin novocaine salt in the same dose for 14 days.

Preventive measures for syphilis

Antenatal prophylaxis
1. Correction of sexual behavior.
2. A complete examination of pregnant women: history taking, clinical and serological examination in the first and second half of pregnancy.
3. Timely diagnosis and treatment of syphilis in pregnant women.
Postnatal prophylaxis
1. Thorough examination of the newborn (up to 3 months of age).
2. Preventive therapy - if a woman did not receive full treatment in advance, is not registered or did not receive prophylaxis during pregnancy.

The diagnosis of syphilis is a set of measures that are carried out in order to establish whether the causative agent of the disease is present in the human body, at what stage of formation the disease is, in order to decide how exactly it should be treated.

It is completely impossible to detect and clarify such a disease on its own - the patient himself can only identify signs of the formation of syphilis, for example, hard chancre, rash, lymphadenopathy. There are also cases when syphilis is asymptomatic. Therefore, the primary detection of the disease occurs, most often, in two ways - during a preventive examination, if a person does not feel any manifestations of the presence of treponema in the body, or through the implementation of specific tests and examinations.

Following the detection of clinical signs of syphilis, the definition and diagnosis is made. How does this happen? The doctor examines and interviews the patient, finds out what exactly he is complaining about, and then appoints him to conduct laboratory examinations and tests.

First of all, the patient will need to pass general and biochemical blood and urine tests, since their indicators, for example, an increased value of leukocytes or ESR, let the physician understand that the patient has health problems. Further, specific tests are assigned to him according to the methods for detecting treponema, as well as methods of serological diagnosis.

What are the ways to detect treponema

After the doctor collects the patient's history and conducts an initial examination of the oral cavity, genitals, skin and mucous membranes, he has basic information about the condition of the patient who turned to him, but this is not enough to make an accurate diagnosis.

Among the methods for detecting the presence of pale treponema in the body are dark-field microscopy, the polymerase chain reaction method, as well as the direct immunofluorescence reaction.

Microscopic studies, or dark-field microscopy. To identify microorganisms in the material taken, its microscopy is carried out in a dark field. The use of this method is explained by the fact that some bacteria are difficult to stain or do not stain at all with special dyes. In addition, the study of material in a dark field makes it possible to study the state of living bacteria, and since dark-field microscopy does not require staining, it is cheaper and takes less time to conduct.

For analysis, the contents of skin syphilitic formations are selected - ulcers, papules, erosions, in some cases - material from peripheral lymph nodes.

What can such an analysis show? Detection in biological material of moving pale treponemas in any quantity is proof of the presence of syphilis in the subject. It is possible to distinguish pale treponema from other, non-pathogenic spirochetes by the number of curls.

It should be noted that this method is the only objective way to determine the diagnosis of "syphilis", if we are talking about early, fresh, primary forms, when serological tests give negative results. Especially valuable are his indications in the diagnosis of neurosyphilis and the state of reinfection.

How is material collected? Erosion or papule is first treated with an antiseptic - this is how the place where the liquid is taken is prepared for the intervention of a physician. After that, pressure is applied to its surface with a blunt scalpel - in this way, the physician achieves the release of tissue juice of a transparent yellow color. In addition, scraping or taking a smear from the mucous membranes can be carried out. The shelf life of the obtained material is quite short, so the analysis should be carried out immediately after its collection.

According to the results of the study, the patient can be diagnosed with primary or secondary syphilis, as well as early congenital syphilis in a child.

Positive results are considered as a reliable basis for determining the disease. If a person does not have treponema, the procedure is repeated up to three times, before applying compresses with saline to the wound.

If there is a suspicion of tertiary syphilis, or a combination of syphilis with oncological neoplasms, dark-field microscopy is combined with Romanovsky-Giemsa staining, or Morozov silvering.

PIF method. It is more safe for the personnel conducting it than a dark-field study. At the same time, treponemas in smears are fixed, they do not have to be alive, therefore, such an examination can be carried out at any time after the selection of the material.

For study, the contents of the fluid separated by syphilides, or tissue sections from the areas of skin manifestations of syphilis, and lymph nodes are taken from the patient. The sensitivity of the method is up to 95%.

PCR method. With the help of polymerase chain reaction, the result of the examination can be obtained within a few hours after taking the material. Its sensitivity reaches 98.6%.

However, despite the apparent advantages, the technique is practically not used in Russia and Ukraine, since its sensitivity and specificity are not well studied in comparison with direct diagnostic methods. PCR screening is used as an additional method for diagnosing congenital syphilis, neurosyphilis, and also when it is difficult to diagnose syphilis in HIV patients.

The study of blood serum in this way is ineffective; for PCR, the contents of syphilides are selected.

Serological diagnostic methods

Serological diagnostics is prescribed to patients to confirm syphilis, to detect latent syphilis, to monitor the effectiveness of the prescribed treatment, and also for preventive purposes.

The essence of serological reactions is to identify and calculate the body's immune response to the ingestion of the pathogen, and to determine the so-called markers of syphilis.

To date, the most studied antigens for pale treponema are:

• protein;
• antigens of a polysaccharide nature;
• lipid antigens.

The body's immune response is produced through the production of cellular (macrophages and T-lymphocytes) and humoral immunity (specific immunoglobulins). In this case, the production of antibodies to syphilis occurs according to the general rule - first IgM appears, then IgG (total antibodies). It is also possible to isolate antibodies of the classes IgA, IgE, IgG.

Syphilitic antibodies can be specific and non-specific, directed against autoantigens, as well as against lipid antigens of treponema.

It is serological tests that make it possible to identify the presence and concentration, as well as the type of antibodies developed against the pathogen. All analyzes carried out are divided into several general groups:

• lipid;
• group treponemal;
• species-specific protein treponemal reactions.

The most commonly prescribed by physicians are:

• enzyme immunoassays;
• reactions of passive hemagglutination;
• microprecipitation reactions.

enzyme immunoassay. This laboratory examination is based on the high specificity of immunological reactions of the antigen-body type. ELISA has several modifications, one of which is ELISA, or solid-phase heterogeneous immunoassay. This type of analysis is prescribed to determine the presence of antigens of classes A, M, G to the causative agent of syphilis. The diagnosis is based on the immune reaction of the antigen and antibody, as well as taking into account the attachment of an enzyme label to antibodies. For the study, the patient's blood serum is used, the material is taken from a vein. The first reaction occurs between Ig At and the purified antigen of the pathogen Ag, which is fixed to the surface of the wells of the immunological plate.

The following immunological reaction makes it possible to identify the bound specific immunoglobulin, as well as antibodies to it - the Ig At conjugate, marked by peroxidase.

Depending on the concentration of immunoglobulins in the material, the color may be more or less intense. After the completion of the reactions, the doctors perform photometry of the wells and count the results.

For serodiagnosis in this case, polystyrene plates with 96 wells are used. Antigens are adsorbed on their wall in advance. Next, the test serum is injected into the cells, and antibodies homologous to the antigen are attached to it. Remaining antibodies are removed by washing. The next step is the introduction of enzyme-labeled antibodies against immunoglobulins into the wells. If there are detectable antibodies in the studied blood serum, they will work as antigens with which labeled antibodies will react.

After washing, a dye is introduced into the serum, which allows you to visualize and take into account the reaction according to the intensity of staining. The concentration of antibodies per unit volume is calculated from the change in the optical density of the liquid in a particular cell.

The ELISA reaction in combination with other reactions allows you to determine the presence of antibodies to syphilis, viral hepatitis, HIV infection, chlamydia, cytomegalovirus. For the primary diagnosis of syphilis, it is prescribed together with the microprecipitation reaction, however, it should be remembered that the detection of antibodies in the blood only indicates contact of the subject with the pathogen in the past or present. The result can be obtained within a few days.

By studying the results, namely the class of antibodies detected, the physician can determine the stage of the infectious process. At the same time, such data as the number of detected antibodies, unfortunately, does not matter for establishing an accurate diagnosis or developing treatment tactics.

The ELISA technique is most often used as an analysis confirming the test for syphilis, while it is not done as a control test to determine the cure for the disease.

The reaction of passive hemagglutination. One of the types of selection reactions. Untreated and previously treated patients in the early and late stages of the disease have the highest sensitivity and the most accurate result - up to 99.6%.

Its disadvantage is the fact that the reaction can only give negative results in a small number of cases, so it is not an adequate method of monitoring treatment. However, among all methods for diagnosing syphilis, it is RPHA that is the most commonly used microbiological reaction - it is simple, highly sensitive, and cheap. In addition, Reiter's antigen can be used in the process.

What is the essence of RPGA? It is based on the detection of agglutination of erythrocytes, on the surface of which antigens of pale treponema are fixed. In this case, agglutination occurs only in the presence of antitreponemal antibodies. For the first time this idea appeared in 1965, and since then it has been actively used for the serodiagnosis of syphilis.

The reaction is assigned to confirm any stage of the disease. Provided that it is combined with the ORS test, there is no need to conduct a complex of serological reactions for the patient. Such an analysis is not used on its own, its value can only be determined in combination with the LFS and RIF.

The only disadvantage of this diagnostic method is the need to wait some time after the alleged infection, since in the first 4 weeks after contact with the patient, a negative test result will be doubtful. At the primary stage of the disease, the reaction shows low titers (up to 1:320), during the secondary titers of the reaction increase. With latent syphilis, the titers decrease again.

It should be noted that after the disease, the reaction of RPHA remains positive for life, therefore, such a result as a quality control of treatment is considered false positive.

The material to be studied in this case is blood taken from a human vein. On average, an objective result can be obtained the very next day after the test.

Microprecipitation reaction. Produced with cardiolipin antigen, another name - RPR or RMP, refers to non-treponemal tests. It consists in the determination of reagents - antibodies of type M and G, which are formed in response to antigens of lipid origin, obtained in response to damage to healthy cells by the causative agent of syphilis.

The reaction is prescribed as a primary examination for syphilis, in the order of medical examinations and monitoring the effectiveness of treatment.

The screening test is able to determine the presence of antiphospholipid antibodies, and it can be called a more progressive replacement for RW, which is also called the Wasserman reaction. The analysis can determine the presence of antibodies in the blood serum that appear 3-5 weeks after infection, that is, approximately 10 days after the appearance of the first chancre, before this time the reaction result may be false. In addition to blood from a finger or a vein, cerebrospinal fluid, which is taken by means of a puncture, can be examined.

In 78% of cases of primary syphilis, the test will be positive, the probability of determining the presence of a secondary form of the disease is much higher - up to 97%.

If RPR shows a positive result, the doctor prescribes subsequent tests - ELISA, RPHA, RIF, to check if it is false. One of the reasons why the result may show positive values ​​that do not correspond to reality is the presence of antibodies to phospholipids in the blood.

During the analysis, agglutination of lipid particles with cholesterol and cardiolipin is recorded. Antibodies to phospholipids bind to cardiolipin, causing their agglutination. In patients with syphilis, a similar reaction occurs - in such patients, a false positive test is checked by a negative result of specific tests for syphilis, which are performed to detect antibodies to treponemal antigens. A false positive reaction may be the result of the presence of certain autoimmune diseases in the body, such as systemic lupus erythematosus. A transient positive reaction is determined in pregnant women with mononucleosis, malaria, chickenpox, tuberculosis, chlamydia.

At the end of successful treatment, the RPR reaction becomes negative in 90% of patients.

How is the diagnosis with the appointment of microprecipitation? First, the patient undergoes a selection reaction RPR, or any of its modifications in quantitative and qualitative form. If the analysis is positive, then any specific treponemal test is prescribed to the patient as a differential diagnosis of infection with syphilis.

Upon completion of treatment, the patient undergoes an MR reaction, and by reducing the resulting titer, the attending physician can track the dynamics of recovery and the effectiveness of therapy. If the results show a decrease in titer readings of 4 or more times per year, the treatment is considered effective.

Interpretation of results: false, erroneous, false positive, false negative

Why should you immediately consult a doctor when the first signs and symptoms of syphilis appear? The fact is that even if you independently pass tests in the nearest laboratory, only a qualified one can correctly decipher their indicators.

Any types of serological tests are usually prescribed as an express diagnostic, or during medical examinations. Their results can be negative, weakly positive if the antibody concentration does not reach a certain level, or positive. In addition, each type of analysis can be false positive or false negative. Positive reactions of non-treponemal tests are usually checked by the results of specific treponemal tests.

Treponemal serological examinations may also be negative, equivocal, weakly positive, or positive. For example, immunoblotting is prescribed to confirm or refute the results of the primary examination. Detection of antibodies such as IgG and IgM in the blood is marked by stripes.

If both the non-specific primary screen and the specific serological test show a negative result, then the person is healthy, or the infection occurred less than 10 days ago.

A positive reaction in pregnant women may also be present on non-treponemal screening, however, if a subsequent immunoblot test was performed and it gave a negative result, this means the absence of the disease.

Can an error creep into the test results? There is always some possibility that the analysis showed erroneous results. Therefore, in the process of diagnosing, the doctor must pay attention to external factors that do not depend on the patient.

False positive tests can occur if a person has:

• diabetes;
• alcohol or drug intoxication;
• measles, mononucleosis, hepatitis;
• heart diseases;
• tumor of any type;
• pregnancy;
• autoimmune disease.

Most types of tests can reveal the presence of a disease, but only if it has reached a certain stage of development. For example, RW will show the presence of infection with a 100% probability, but only a month after the pathogen enters the body. Tertiary syphilis shows up in RW results with up to a 75% chance.

Early stages are more appropriate to diagnose through the implementation of ELISA tests. If a person has no other diseases, its reliability tends to 96%.

A negative indicator may indicate the absence of the disease. Doubtful result is the reason for the appointment of a second examination. If antibodies to syphilis are found in a patient, this is not a reason for panic - a qualified and timely selected treatment can cope with the disease, if it is present, without any dangerous consequences.

Crosses, dashes and pluses in deciphering the analysis: how to understand

The results of some serological tests may be given in the form of a table, where the columns indicate crosses or dashes. How is this result decoded?
So, for example, MR or microprecipitation reaction is calculated in digital terms, showing the quantitative titer of infection.

RW (Wasserman reaction) means obtaining test indicators in the form of:

• dash (negative test);
• one or two crosses (weakly positive);
• three crosses (positive);
• four crosses (sharply positive test).

The presence of even one cross in the results is the basis for the appointment of the following analyzes of a clarifying nature. A dash in the table does not guarantee the absolute absence of the disease.

The results of the RIF are also indicated in the form of plus signs or crosses - from one to four. If a person shows a dash (minus) - it means that syphilis is absent. Results in the form of one, two, 3 crosses or 4 pluses indicate the presence of the disease.

RPGA does not give any quantitative associations as a result - it shows either the complete absence of the disease, or its presence in the past or present.

ELISA results are more difficult to decipher. They are presented in the form of a table of classes of antibodies IgA, IgM and IgG. Near each value there is a dash or a cross. Comparing the presence or absence of a particular type of antibody, the attending physician can draw a conclusion about the stage of the disease, the duration of infection.

After conducting a comprehensive examination for syphilis, the doctor summarizes all the results obtained in a single extended table, using the pros and cons method. Putting down crosses and dashes, depending on whether the result of a particular analysis was positive or negative, the attending physician can draw up a picture of the disease.

Test preparation requirements

How do I prepare for a prospective syphilis test? The sampling of material for research can be carried out from a vein or a finger, if we are talking about a blood test. Compliance with a special diet is not required for this, but the blood is taken on an empty stomach - you can’t eat at least 4 hours before the procedure, and in some cases you should not eat 12 hours before taking the material.

If the patient is to be given material to detect treponema DNA, it should be carried out before starting antibiotic therapy.

Collection of cerebrospinal fluid is carried out only in a hospital. There are no dietary or lifestyle restrictions prior to the scheduled procedure.

Scrapings from the surface of the eye are just as easy to give up. With regard to swabs and skin scrapings, the main requirement is not to use any local cosmetic or medical products until the removal of the material.

Removal of scrapings and swabs from the genitals requires more thorough preparation, for example, so that the patient refrains from intimate contacts, diagnostic medical manipulations 3 days before the scheduled procedure. In addition, women should not douche or use vaginal suppositories and tablets.

Rapid tests for syphilis: is it possible to diagnose the disease yourself

Modern medical science has stepped so far forward that today there are even rapid tests to determine the presence of syphilis at home.

A test for home examination of a person for the presence of syphilis allows you to determine whether there is an infection of the body.

In pharmacies, you can buy a special kit for self-examination, for example, to examine saliva or blood. As a preparation for such a procedure, you must follow all the requirements described in the instructions. If a blood test is performed, you should not eat for at least 5 hours before the procedure.

Self blood test kits involve taking just 1-2 drops of blood through a small puncture in the skin. It is done using a special device with a sterile sharp tip or needle. Within a few minutes, the device can detect the presence of antigen in the blood.

Some kits only offer devices for taking material for analysis, which must then be sent to the laboratory for analysis. It should be noted that the selected material is suitable for examination for a short period of time - if it is not delivered to the laboratory on the same day, the result cannot be considered valid.

In any case, if you suspect syphilis, you need to see a doctor as soon as possible, even if tests at home showed a negative result.

Diagnosis of syphilis includes a whole range of activities, in which the central role is, of course, assigned to special analyzes and tests. The patient can take cerebrospinal fluid, blood from a vein or finger, smears and scrapings from the skin and mucous membranes, tissue fluid from wounds and damage to the integument, in order to detect both the pathogens themselves and antibodies to them.

In general, the diagnosis of syphilis is based on the analysis of clinical and laboratory data. The diagnosis is established by a specialist!

Speciality: infectious disease specialist, gastroenterologist, pulmonologist.

General experience: 35 years .

Education:1975-1982, 1MMI, San-Gig, highest qualification, infectious diseases doctor.

Science degree: doctor of the highest category, candidate of medical sciences.

Among sexually transmitted diseases, it occupies the first position in terms of prevalence. The disease is transmitted from a sick person to a healthy person mainly through sexual contact. Diagnosis of syphilis is a complex, step-by-step process that does not always bring results.

Suspicion of syphilis - which doctor should I go to?

The disease has become widespread because many young people simply do not know how to determine syphilis, what examinations they need to undergo. Sexual infections are treated by venereologists or dermatovenereologists, since in most cases such infections are accompanied by damage to the skin. Doctors advise for the preventive purpose to be examined for each patient of reproductive age. The disease often occurs in a latent form, so it is not always possible to identify it.

Methods for diagnosing syphilis

Diagnostic measures to identify the disease are based on clinical and laboratory data. The diagnosis of "syphilis" is made only after receiving positive results of a laboratory test. Early diagnosis of syphilis rules out progression of the disease. Primary syphilis is determined by the study of detachable hard chancre of erosive papules. Among the main methods of laboratory diagnosis of syphilis, it is necessary to highlight:

1. Bacterioscopy.
2. Serological examination (specific and non-specific).
3. Histology (at).
4. Microscopy (study of the native preparation, discharge of erosive or ulcerative rashes, punctate from the lymph node).

Microbiological diagnosis of syphilis

The basis of this type of examination is the bacterioscopic method for diagnosing syphilis. It involves the detection of T.pallidum in the material taken from the foci of inflammation:

• chancre;
• erosive disorders;
• lymph nodes;
• spinal cord.

Previously, the doctor wipes the site of material sampling with a swab with saline, then irritates the erosion surface with a special loop until tissue fluid appears from it.

At the same time, mixing of the material with blood is avoided. The liquid is placed on a glass slide. The preparation obtained in this way is examined using a microscope. Methods of microbiological diagnosis of syphilis are based on the detection of the pathogen in the material. If the result is negative, the study is carried out for several days in a row to completely exclude the disease.

Serological diagnosis of syphilis

To identify and confirm the diagnosis of "syphilis" in the case of late and latent forms of diseases, the basis of diagnosis is the serological method. In most cases, they are used to diagnose syphilis. The method involves the study of venous blood of patients who detect antibodies to pathogen antigens. Such an analysis for pale treponema helps to identify the disease even in the absence of obvious clinical symptoms.

Depending on the composition of the substances used for diagnostics, serological methods are divided into:

1. Specific (treponemal).
2. Nonspecific (non-treponemal).

Treponemal tests

Treponemal tests are a diagnostic method based on specific Treponemapallidum antigens. The method is used both for making and confirming the diagnosis, for the differential diagnosis of syphilis. All specific tests have high sensitivity and accurate results. The mechanisms for conducting specific tests are not the same, so they have different indications for use. Treponemal tests include the following methods of laboratory diagnosis of syphilis:

1. Complement fixation reaction (Wassermann reaction, RV) with treponemal antigen - RSKt.
2. Pale treponema immobilization reaction - RIBT.
3. Immunofluorescence reaction - RIF. It is used in several modifications: RIF-200 (FTA-200); RIF-abs; RIFC is an immunofluorescence reaction with whole blood or cerebrospinal fluid.
4. The reaction of passive hemagglutination - RPHA.
5. - IFA.
6. Immunoblotting.

Non-treponemal tests

Non-treponemal tests for syphilis are used as screening tests and are not suitable for definitive diagnosis. They are actively used to examine large groups of the population for the purpose of preventive examinations in the event of an unfavorable epidemiological situation. The test is easy to carry out and has high sensitivity. The result of the diagnosis is evaluated by the doctor. The sensitivity of non-specific tests for early forms of the disease is about 70%, and for secondary syphilis - 100%.

Non-treponemal tests for diagnosing syphilis include:

1. RPR (Rapid Plasma Reagins).
2. Test with inactivated serum - MRP (precipitation microreaction with cardiolipin antigen).

These flocculation tests are characterized by ease of evaluation. During the reaction, an antigen + antibody complex is formed, which forms flakes that can be seen with a magnifying glass. The role of the antigen in the test is performed by the cardiolipin antigen, which is obtained from the heart muscle of the bull. There is no connection with the antigens of the causative agent of syphilis, which is why the tests are called non-treponemal.

Express diagnostics of syphilis

Modern methods of diagnosing syphilis involve the detection of the disease in the early stages. RapidPlasmaReagin(RPR) is used as an express diagnostic method. The test is aimed at determining the concentration in the blood of antibodies to the causative agent of syphilis. When infected, pale treponema forms protective IgG and IgM antibodies in the body. Their presence in the sample of the taken blood is indirect evidence of the presence of pale treponema in the body. This diagnosis of syphilis helps to establish the exact duration of the disease, the time of infection.

Tests for syphilis - transcript

Modern laboratory diagnosis of syphilis is based on the following methods:

• non-treponemal test - RPR or VDRL;
• treponemal tests - RIF and RPHA.

In the CIS countries, the Wasserman reaction is more often used to diagnose syphilis, as well as the reaction of immobilization of pale treponemas - RIBT. The evaluation of the results obtained is made only by a doctor who takes into account the clinical manifestations of the disease, the stage of the pathology, the patient's condition. Exemplary research results can be found in the table below.

Differential diagnosis of syphilis

When a doctor suspects syphilis after the initial examination, he refers the patient to RV for blood donation. If the results of the study confirmed the presence of pale treponema in the body, differential diagnosis is carried out with the determination of the stage of the disease. In primary syphilis, RIF and ELISA are more likely to be positive, but this does not allow a diagnosis of syphilis to be made.

Diagnosis of secondary syphilis does not cause difficulties - the result is sharply positive for all serological reactions. RIBT is positive in more than 50% of patients. The tertiary form of syphilis is practically not difficult. Serological reactions are positive in 50–90% of cases. Diagnosis of latent seropositive syphilis is based on serological tests with confirmation of the result using RIBT.

Indirect methods for diagnosing syphilis.

For the diagnosis of syphilis, many research methods are used, differing in technique and purpose. Direct methods are aimed at detecting the pathogen in the test material using microscopy (dark field microscopy, etc.) or PCR.

In addition to the methods of direct detection of pale treponema (T. pallidum), when examining for syphilis, indirect ( serological) research methods that detect antibodies to the causative agent of syphilis in blood serum and cerebrospinal fluid. Indirect methods for diagnosing syphilis include serological tests of ELISA, RPHA, CSR, RIF and RIF-abs, RIBT, PCR, express method, immunoblot, and others.

Serological methods for diagnosing infectious diseases.

Serological diagnostic criteria based on specific antigen-antibody reactions. Antigens (components of cell walls, flagella, capsules, DNA and toxins) of those microorganisms that need to be determined react with antibodies contained in sera. Binding occurs between antigens and their corresponding antibodies, which is the basis of serological diagnostic methods. Serological tests are used to detect an unknown antigen (source of which is a bacterium, virus, toxin, etc.) using a known antibody or to detect an antibody in serum using a known antigen.

Serological reactions are classified depending on the state of the antigen and the characteristics of the environment in which the antigen and antibody interact, as well as according to the method of carrying out.

To conduct serological reactions, many laboratory methods are used, such as agglutination, precipitation, complement fixation, immunofluorescence, enzyme immunoassay and radioimmunoassay, and others. These reactions allow efficient preliminary identification of microorganisms.

The sera required for setting up serological reactions are obtained experimentally, in particular, they are produced by the institutes of vaccines and sera, and are offered as part of commercial diagnostic kits.

Serological methods are an important tool in the diagnosis and treatment of infectious diseases in humans and animals, since they can not only identify the causative agent of the disease, but also detect specific antibodies to the corresponding pathogens in the blood of patients and recovered patients. Serological methods are currently the most effective diagnostic methods when it is impossible or difficult to isolate the pathogen, and relatively rarely give false positive and false negative results.

Using serological methods to diagnose syphilis

The basis of serological laboratory methods for diagnosing syphilis is the ability of the body to give an immune response to the appearance of the pathogen. With the help of serological reactions in the serum (plasma) of blood (or cerebrospinal fluid), traces of the immune response to infection are detected, namely antibodies to pale treponema antigens, or the antigens themselves.

In order to establish the specific nature of the existing clinical manifestations (i.e., that they are a consequence of syphilis) and, in the future, to control the dynamics of the pathological process, a large number of serological research methods have been proposed. These same methods are also widely used for population screening.

In accordance with current national guidelines and clinical guidelines, in many countries around the world, advanced serological methods are used in population surveys to identify patients with syphilis and in establishing a clinical diagnosis. They are used both in the presence of clinical signs of the disease in patients, and in latent periods.

Setting serological reactions is one of the most reliable methods for diagnosing syphilis. Standardized serological tests with a regulated method of setting are called serological tests for syphilis. Considering that almost all serological reactions to syphilis under certain conditions can be false positive or false negative, they should be put in a complex and, if necessary, in dynamics.

Serological tests, which are used to determine antibodies in the patient's blood serum, differ from each other in sensitivity, specificity, complexity of setting and cost. In addition to classical methods, immunological tests and technologies are used for effective syphilis serodiagnosis, which have received a new impetus to development in the 21st century.

Antibodies are detected by various immunochemical (serological) methods, including sedimentary reactions, enzyme immunoassay, immunochemiluminescence, immunochromatographic assays, linear immunoblotting, flow fluorometry, immunochip technology, and others.

Serodiagnosis (a study using serological methods) is used for:

• confirmation of the clinical diagnosis of syphilis,
• diagnosis of latent syphilis,
• monitoring the effectiveness of treatment, as one of the criteria for the cure of patients with syphilis,
• prevention of syphilis (screening examination of certain groups of the population in order to identify pathology).

The most important properties required by serological tests - sensitivity, specificity, reproducibility

The decisive criterion for choosing a laboratory diagnostic method is its effectiveness - sensitivity, specificity and reproducibility.

Sensitivity is the proportion of positive results in patients. The sensitivity of the method is determined by the percentage of positive results of the study of samples that are known to contain specific markers of the pathogen (eg, pathogen antigens or antibodies to them).

Specificity- proportion of negative test results in healthy patients. The specificity of the method is determined by the percentage of negative results of the study of samples that obviously do not contain specific markers of the pathogen. Thus, the higher the sensitivity and specificity, the more reliable and reliable the research method.

Important diagnostic criteria also include reproducibility results from repeated examinations of the same samples. It should be noted that, despite significant advances in high technology, there are no methods that provide 100% (absolute) sensitivity and specificity in all bioassays studied.

Currently, test systems, kits, and ingredients that have less than 95% sensitivity and specificity when setting up a reaction are officially registered in Russia. Thus, there is always the possibility of obtaining an inadequate result.

Classification of tests according to the type of antigen used. Treponemal and non-treponemal tests for syphilis

In modern venereology, more than a dozen variants of serological reactions to syphilis are used for diagnostic purposes, which can be divided into different categories according to different criteria. The classification is carried out according to the research methodology, scope, speed, low cost, requirements for laboratory equipment, etc.

Treponemal reactions are theoretically more specific, but they also give false positive results. Moreover, they do not allow to differentiate between untreated and cured syphilis. The results of treponemal reactions will be positive in both cases. Non-treponemal reactions distinguish between untreated or recent and cured infections.

During the examination, it is recommended to carry out both treponemal and non-treponemal reactions. To establish and confirm the diagnosis of syphilis, positive results are required for both types of tests - treponemal and non-treponemal. Therefore, non-treponemal tests are used in combination with treponemal tests, and are carried out before, during and after the end of treatment at certain time intervals.

1. Non-treponemal tests

The most famous of the non-treponemal tests with a visual interpretation of the results are

• RW - Wassermann reaction with lipid antigens (complement fixation reaction with cardiolipin antigen, RSKk)
• Kann reaction (not currently used),
• cytocholic reaction of Zaks-Vitebsky (not currently used),
• microreaction of precipitation with plasma or inactivated serum (MRP or RMP),
• RPR (Rapid Plasma reagin test),
• TRUST (Toluidin Red Unheated Serum Test).

Among non-treponemal tests, there are 2 tests with microscopic reading of reaction results:

1. VDRL - (Venereal Disease Research Laboratory);

2. USR - test for the determination of active plasma reagins (Unheated Serum Reagins).

Reactivity in nontreponemal tests usually indicates tissue damage and is not always specific for syphilis. Ease of implementation and low cost allows them to be used as screening reactions in establishing a preliminary diagnosis of syphilis.

2. Treponemal tests

Treponemal tests use specific treponemal antigens. These tests are required to confirm the diagnosis (RPHA, RIT, RIF and ELISA). They are more complex and expensive than Group 1 tests, but also more specific and sensitive. The detection of antibodies in the cerebrospinal fluid is also performed using treponemal tests.

Traditional treponemal tests confirming the diagnosis of syphilis require expensive laboratory equipment and experienced personnel, so they are rarely performed outside of specialized laboratories. However, they can now be replaced by simple and rapid treponemal tests that can be carried out in the field and use whole blood. Carrying out these reactions does not require long-term training, special conditions for the storage of reagents and equipment.

The comparative cheapness, convenience and practicality of treponemal express reactions draw attention to them not only as methods of confirming the diagnosis. These reactions can be used to screen for syphilis in primary care (they can be done in the field at the same health care facility) or in areas where laboratories are not available. However, since antibodies to T. pallidum are determined over a number of years, regardless of whether the patient was treated or not, treponemal rapid reactions cannot be used to assess the effectiveness of treatment and differential diagnosis of untreated and cured syphilis.

Classification of serological methods for diagnosing syphilis according to the type of antibodies detected

In modern dermatovenereology, various serological reactions to syphilis are used for diagnosis. Some of the methods that were relevant ten years ago are no longer used due to complexity or lack of specificity. Depending on the detected antibodies, the methods of serological diagnosis of syphilis are divided into three groups:

I. Lipid (reagin) reactions - antibodies to lipid antigens (reagins) are determined:

1) flocculation: microreaction on glass with lipid antigens - an express diagnostic method (precipitation microreactions - MRP), VDRL, CMF (cardiolipin microflocculation test), RPR, etc.;

2) complement fixation reaction (RSK) with lipid antigens: Wasserman reaction (RV), qualitative and quantitative method of setting, thermostatic and in the cold (Colmer reaction);

3) sedimentary reactions that are not currently used: the Cahn precipitation reaction, the cytocholic Sachs-Vitebsky reaction, etc.;

II. Group treponemal reactions - antibodies to group treponemal antigens (which are part of the microbial cell of both pathogenic and saprophytic treponemas) are determined:

1) CSC with Reiter's protein antigen;

2) immunofluorescence reaction (RIF);

3) immune adhesion reaction (RIP).

III. Species-specific protein treponemal reactions - antibodies to specific species antigens of Treponema pallidum are determined:

1) reaction of immobilization of pale treponemas (RIT);

2) RIF-abs immunofluorescence reaction and its variants (IgM-FTA-ABS, 19S-IgM-FTA-ABS, etc.);

3) reaction of indirect hemagglutination of pale treponemas (TPHA) and its modification TPPA.

4) enzyme immunoassay (ELISA);

5) immunoblotting.

Practical use of serological tests for syphilis

Different serological tests are used for different practical purposes.

Abroad, in mass surveys of the population and, if necessary, emergency detection of syphilis, non-treponemal screening reactions (VDRL, RPR, etc.) are used. Diagnosis requires confirmation by treponemal tests FTA-ABS, TPHA, or TPPA. Currently, it is recommended to use ELISA as a replacement for VDRL in screening tests. This is due to the fact that the ELISA test is distinguished by sensitivity, specificity, the ability to automate research, as well as the development of diagnostic test kits. In addition, a reverse scheme of the order of examination for syphilis is substantiated, when treponemal tests are used first.

In order to monitor the effectiveness of therapy and to assess the activity of the infection, quantitative VDRL is recommended. An ELISA test for antitreponemal IgM antibodies is used as a confirmatory/additional test.

In domestic practice, a complex of serological reactions (CSR) is used, including a microprecipitation reaction (RMP) with cardiolipin antigen and CSC with cardiolipin and treponemal antigens. Recently, it is recommended in the CSR to replace RSK with ELISA or RPHA. RIF (and its modifications - RIF-Abs and others), RIBT are also used.

RIBT is used as an examination reaction in cases of divergence of treponemal reactions.

Approaches to laboratory serological diagnosis of syphilis in the Russian Federation

The introduction of unified methods of clinical laboratory research into practice in the USSR and the Russian Federation made it possible to introduce more advanced diagnostic methods, streamline the work of clinical diagnostic laboratories, increase labor productivity, reduce duplication of laboratory tests, and became the basis for the development of rational forms of ready-made reagent kits.

In 1985, in the USSR, in order to improve the diagnosis of syphilis, the non-treponemal CSC reaction with a nonspecific (Wassermann) antigen and sedimentary reactions (cytocholic and Cana) were excluded from the diagnostic complex as less sensitive and not providing additional information.

Instead, as part of the complex of serological tests for syphilis (CSR), the use of the complement fixation reaction with treponemal and cardiolipin antigens (RSKt) and the microprecipitation reaction with cardiolipin antigen (RMP) was provided. The higher sensitivity and information content of this complex of reactions ensured the detection of not only reagins, but also antitreponemal antibodies.

1985

1. RMP with cardiolipin antigen with blood plasma and inactivated blood serum. Selection test in case of isolated application.

2. CSC with treponemal and cardiolipid antigens; qualitative and quantitative methods of setting, thermostatic and in the cold;

3. Treponema pallidum immobilization reaction (RIT); test-tube and melange methods of setting;

4. Immunofluorescence reaction (RIF) in the following modifications: RIF with absorption (RIF-abs) with blood serum and capillary blood, RIF-200, RIF with whole cerebrospinal fluid (RIF-c); qualitative and quantitative methods of setting. Diagnosis of latent and late forms of syphilis, recognition of decision makers (false-positive results)

5. Complex of classical serological reactions (CSR): RSC (Wasserman reaction) with cardiolipin and treponemal antigens + RMP. Preventive examination of the population for syphilis, diagnosis of all forms of syphilis, monitoring the effectiveness of treatment, examination of persons who are contacts for syphilis.

In 2001, the Ministry of Health of the Russian Federation approved a new regulatory document regulating the procedure for conducting diagnostic tests - Order of the Ministry of Health of the Russian Federation No. 87 dated March 26, 2001 "On improving the serological diagnosis of syphilis".

In order to improve the laboratory diagnosis of syphilis, improve the quality of work and prevent further spread of the incidence of syphilis, it is recommended to replace the RSK in the complex of seroreactions (CSR) in the diagnosis of syphilis by ELISA and TPHA as screening and confirmatory tests, because these test systems are highly sensitive, specific and reproducible.

Order No. 87 of March 26, 2001 “On improving the serological diagnosis of syphilis” provides for the use of the following methods for sero- and cerebrospinal fluid diagnosis of syphilis in Russia:

1. RMP and foreign analogues (VDRL, RPR and similar microreactions) as screening tests when examining the population for syphilis. RMP is performed with plasma or inactivated blood serum.
2. Enzyme immunoassay (ELISA). Antigen from cultured or pathogenic treponema pallidum. Diagnostic reactions, including for liquor diagnostics. Due to the ease of setting and the availability of commercial test systems, they can be used as screening tests.
3. The reaction of passive hemagglutination (RPHA). Antigen from cultured or pathogenic treponema pallidum. Selection and diagnostic reactions.
4. Qualitative and quantitative variants of RIF (RIF-abs, RIF-c, RIF with capillary blood from a finger). Antigen - pathogenic pale treponema of the Nichols strain.
5. A complex of serological reactions (CSR) for syphilis, consisting of a complement fixation reaction (CFR) with treponemal and cardiolipin antigens, and RMP. It is possible to replace the complement fixation reaction with ELISA or RPHA also in combination with RMP. CSR refers to diagnostic tests.
6. Pale treponema immobilization reaction (RIBT), in which pathogenic treponema pallidum of the Nichols strain is used as an antigen. RIBTs are diagnostic confirmatory tests.

Thus, the sequence of examination of patients for syphilis in healthcare facilities is recommended to be planned as follows:

1. During the initial examination, a selection (screening) reaction of microprecipitation (RMP) or its modification (RPR, TRUST, VDRL) is performed in quantitative and qualitative versions and, in case of a positive result, any specific confirmatory treponemal test (RPHA, ELISA, CSR, RIF , RIT);

2. After the end of therapy, RMP or its modification is placed, and the dynamics of the infectious process and the effectiveness of therapy are judged by the decrease in titer. A confirmation of the effectiveness of the therapy is a decrease in titer by 4 or more times within 1 year.

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