Particle agglutination assay for the detection of IgM and IgG antibodies to treponema pallidum. Offers new levels of sensitivity, specificity and simplicity in an assay for detection of T. pallidum antibodies. Increased sensitivity reduced incubation time, no pre-dilution and incubation of the sample, liquid controls, gelatin particle format allows for the use of plasma or serum samples. No daily working dilution of reagents to prepare. The sensitivity for detection of IgM antibodies has been greatly enhanced by the further purification of the T. pallidum antigen used in the assay.