Evaluation of the hemagglutination treponemal test for syphilis

The sensitivity and specificity of the hemagglutination treponemal test for syphilis (HATTS) was compared with the fluorescent treponemal antibody-absorption test (FTA-ABS) with 491 sera. Medical histories were obtained for 153 patients with seroreactivity in either treponemal test. Overall correlation with patient history was 96.7% for the FTA-ABS and 93.9% for the HATTS. False-negative HATTS occurred in primary, late-latent (greater than 2 years), and treated syphilis. The reproducibility of the HATTS and FTA-ABS is equivalent. HATTS is an acceptable treponemal confirmatory test for syphilis, but the FTA-ABS should be used to resolve diagnostic discrepancies.