[Serologic diagnosis of syphilis by the passive hemagglutination test].

The passive haemagglutination test in the diagnosis of syphilis was used with: 139 sera posing serological problems, 965 sera from subjects with syphilis at all stages of the disease and non-syphilitics. The percentages of agreement seen both in comparison of THPA with the TPI (94,5 p.cent) and the FTA abs test (97 p.cent) demonstrate its high degree of specificity and sensitivity. The reaction may be performed rapidly on a routine basis and requires little in the way of specialised material. These qualities should lead, in the near future, to the adoption of the T.P.H.A. as a routine examination in all laboratories, reserving the use of the F.T.A. abs test and the T.P.I. for difficult cases.