WassermanWassermann

Wassermann test, also known as the Wassermann reaction, is a historical serologic test for syphilis. It was developed in 1906 by August von Wassermann in Germany and became a widely used screening method for syphilis for much of the 20th century. The test detects antibodies to cardiolipin in patient serum through a complement fixation mechanism, using a non-treponemal antigen composed of cardiolipin, lecithin, and cholesterol.

Principle: If antibodies against cardiolipin are present, they form antigen-antibody complexes that fix complement. When a secondary indicator system (such as sheep red blood cells with anti-sheep antibodies) is added, the fixed complement prevents hemolysis. The absence of hemolysis indicates a positive result, whereas visible hemolysis indicates a negative result.

Interpretation: A positive Wassermann reaction indicates exposure to Treponema pallidum or related conditions, but non-treponemal tests are not specific for syphilis and can be positive in other diseases or conditions (for example autoimmune disorders, pregnancy, malaria, or other infections). Positive results typically require confirmation with treponemal tests (such as FTA-ABS or TP-PA), and titer monitoring can help assess disease activity or response to therapy.

History and impact: The Wassermann test was a pioneering tool in infectious disease serology and played a central role in the diagnosis of syphilis for decades. It was gradually supplanted by more specific treponemal tests and by automated non-treponemal tests like the rapid plasma reagin (RPR) and VDRL, but it remains a landmark in the history of medical diagnostics.

See also: Syphilis serology.