Further evaluation of the microhaemagglutination test to determine treponemal antibodies in CSF

The results of a microhaemagglutination test (MHA:TP) using diluted (MHA:TP-DCSF) and undiluted (MHA:TP-UCSF) samples of cerebrospinal fluid (CSF) from 1452 patients with syphilis, neurological, metabolic, or immunological disorders, and undetermined diagnoses to detect antitreponemal antibodies were compared with those of the Venereal Disease Research Laboratory (VDRL-CSF) test and the fluorescent treponemal antibody (FTA-CSF) test. Using undiluted samples of CSF the MHA:TP test gave more reactive results than with diluted samples. The MHA:TP-UCSF test was slightly more specific and sensitive than the FTA-CSF test. The use of undiluted CSF did not reduce the specificity of the MHA:TP test, as was shown by testing CSF samples from patients with diseases other than syphilis.