Microreaction

The cardiolipin antigen precipitation microreaction (MR) is an analysis used to diagnose syphilis. The microreaction allows to select a group of people with risk of syphilis among others during a mass screening of the population. MR does not detect the presence of the treponema pale, the syphilis pathogen, itself in blood, but helps to find only a fragment of its wall, it is a cardiolipin antigen.  MR is included in the list of mandatory analyses at the annual medical examination for many professions.

There are several variants of the microreaction:  Venereal Disease Research Laboratory (VDRL), Toluidine Red Unheated Serum Test (TRUST), Reagin Screen Test (RST), rapid plasma regain (RPR).

Statistically, the RPR analysis is positive in 78% of cases of primary syphilis and 97% of cases of secondary syphilis. VDRL-analysis is positive in 59 - 87% of cases of primary syphilis, sensitivity is 100% of secondary syphilis, from 80 to 90% of late latent syphilis, in 37 - 94% of the tertiary syphilis [Henry J., 1996].

The determination of the titer of antibodies to cardiolipin antigen has its own diagnostic value: a high titer (more than 1:16) indicates an active process. A low titer (less than 1:8) in most cases indicates a false-positive result, or late latent syphilis. Observation of antibody titers over time is necessary to monitor the effectiveness of the treatment of the disease: a decrease is a criterion for a positive effect of the therapy. Thus, titer should decrease fourfold by the fourth month compared to the initial value, eightfold - by the eighth month.

A common clinical manifestation of syphilis is the presence of changes in the sites of infection (genital organs, oral cavity, anus area) in the form of painless ulcerations (hard chancre).

A more reliable analysis for the syphilis diagnosis is the Total Antibodies to Treponema Pallidum
Read more: MODERN LABORATORY SYPHILIS DIAGNOSTICS