Clinical value of the Treponema pallidum haemagglutination test

In 1,129 patients attending the Department for Sexually Transmitted Diseases, the serum was examined by three screening tests (VDRL slide, RPCF, and TPHA) and twelve cases of syphilis (1 per cent. of patients attenting the clinic) were discovered. Six of these patients were considered to have latent syphilis (5 acquired, 1 congenital) and were detected only by the TPHA; all six cases were confirmed by the FTA-ABS, The TPHA failed to detect three of the remaining six cases (2 primary and 1 very early, the latter in a contact of a patient with primary syphilis). All six cases were, however, detected by the VDRL. In seven cases, the TPHA was positive in the absence of other evidence of present or previous syphilis. In these cases the FTA-ABS was also negative. The clinical application of the TPHA test in the detection of syphilis is discussed.