Treponema pallidum haemagglutination test as a screening procedure for the diagnosis of syphilis.

The serological diagnosis of syphilis relies upon the widespread use of non-specific screenig tests, such as the cardiolipin Wassermann reaction (CWR) and the Venereal Diseases Research Laboratory (VDRL) slide test, in combination with the Reiter protein complement-fixation (RPCF) test (British Cooperative Clinical Group, 1972). Where necessary, the fluorescent treponemal antibody-absorbed (FTAABS) or Treponema pallidum immobilization (TPI) tests can be used for verification of treponemal infection. The T. pallidum haemagglutination (TPHA) test developed by Rathlev (1965, 1967) and modified by Tomizawa (Tomizawa and Kasamatsu, 1966; Tomizawa, Kasamatsu, and Yamaya, 1969) appears to possess characteristics of both a screening and a verification test. It is simple to perform and reproducible, and has a wide spectrum of reactivity in the different stages of syphilis (Tringali, 1970) and a specificity and sensitivity comparable with the FTA-ABS and TPI tests (Garner, Backhouse, Daskalopoulos, and Walsh, 1972; Johnston, 1972; O'Neill, Warner, and Nicol, 1973). In spite of these features, the TPHA test has not yet been widely used as a routine screening procedure. This paper assesses the suitability of the TPHA test as a screening test for syphilis in a serology laboratory serving the general hospital population, an antenatal clinic, and a Sexually-Transmitted Diseases Department.