Wasserman reaction (RW) – known specific rapid test for the presence of syphilis in a patient. The method was discovered back in 1906 by the German scientist August Wassermann and actually made a revolution in dermatovenereology.
Today, the Wassermann test is considered to be a rather outdated method for diagnosing syphilis due to the emergence of new serological reactions. Traditionally, the reaction is still used today, as it is a quick and simple method for diagnosing syphilis.
The result is often false positive in individuals with certain pathological conditions of the body or during pregnancy. Read on estet-portal.com how the Wasserman test is performed and what causes false positive reactions.
Hemolytic medium as an indicator of the determination of the immune complex
The Wasserman reaction is based on the phenomenon of complement fixation. To carry out the reaction, the presence of the test serum, two antigens – treponemal and cardiolipin, complement, hemolytic serum and sheep erythrocytes.
Antigens together with reagents form an immune complex capable of binding complement. To determine the immune complex, hemolytic serum is used as an indicator.
A positive Wassermann test indicates the absorption of the compliment and the formation of an immune complex with erythrocyte precipitation.
A negative reaction indicates the presence of a free compliment in the patient's blood, which means that there was no interaction between the serum and the antigen.
The result can be sharply positive (++++), positive (+++), slightly positive (++) and negative (-).
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Conditions in which a false positive result is observed
Unfortunately, the Wasserman reaction is not a highly specific diagnostic method, so false positive diagnostic results often occur. Common causes of false positive seroreactions can be:
1. infectious diseases, the causative agents of which have a similar antigenic structure with pale treponema (yaws, bejil, leptospirosis);
2. physiological conditions (pregnancy, childbirth, menstruation in women, consumption of fatty foods and alcohol);
3. pathological conditions (gout, typhus, malaria, pneumonia, endocarditis, diffuse connective tissue diseases, oncopathology, lead and phosphorus poisoning).
Pregnancy is the cause of acute false-positive reactions (first 2 weeks and first 10 days after birth), enterovirus infection, measles, infectious mononucleosis, vaccination, alcohol and drug use.
Chronic false-positive reactions can occur in SLE, rheumatism, scleroderma, cirrhosis, sarcoidosis, diabetes mellitus, and blood disorders.
Syphilis is often diagnosed during an accidental physical examination
Modern analogue of the Wassermann reaction: anticardiolipin test
Today, an analogue of the Wassermann reaction is more often used to diagnose a venereal disease.
An alternative to the Wasserman reaction is the nonspecific antiphospholipid or anticardiolipin test (RPR) – screening non-treponemal test.
The anticardiolipin test detects IgG and IgM antibodies to lipoprotein-like material released from damaged cells in a patient with syphilis.
A positive reaction is also accompanied by the absence of hemolysis and precipitation. The RPR test is recommended for the initial screening of syphilis and monitoring of the course of the disease during the treatment of syphilis.
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