TPHA

Syphilis is a chronic infection which progresses through distinct stages of infection: primary, secondary, tertiary and quaternary. These stages produce diverse clinical symptoms, typically producing initial chancres then syphilitic rash followed by long periods of dormancy and may eventually lead to cardiovascular problems and neurosyphilis. Caused by the spirochaete Treponema pallidum, infection is usually acquired by sexual contact. The disease may be transmitted by transfusion of infected blood and also intrauterine infection occurs. Tests for syphilis fall into four categories: direct microscopic examination; treponemal antibody tests; non-treponemal antibody tests and direct antigen tests. Because of the long periods of dormancy and the non-specific nature of non-treponemal tests, methods which detect specific anti-treponemal antibodies in patient samples are important for the diagnosis of the infection. TPHA is one such test.