Screening tests for syphilis. A comparison of the Treponema pallidum haemagglutination assay with two automated serological tests.

Two Treponema pallidum haemagglutination assay (TPHA) tests (Wellcome and Fuzizoki) were compared with the automated reagin test and the automated Reiter protein complement-fixation test in a routine screening system. The Wellcome TPHA was shown to lack sensitivity, and it is recommended that it should be used at a lower screening dilution. The Fuzizoki TPHA recorded a significant number of false positive and false negative results, and was therefore inferior to the fluorescent treponemal antibody absorption (FTA-ABS) test as a definitive test for syphilis. It is suggested that the TPHA be used in conjunction with a reagin test to replace some of the more inadequate screening tests currently in use. The automated screening tests were shown to have a similar sensitivity to the TPHA as well as several other advantages; they are recommended for testing large numbers of specimens.