The detection of cryptococcal
antigen by means of the agglutination of antibody-coated
latex particles is an important aid in the diagnosis of
cryptococcosis. A commercially available
latex agglutination test (IBL kit) was compared with the
latex agglutination test from the Center for Disease Control in regard to sensitivity, specificity, and height of
antigen titer. Over a 13-month period, 335 specimens were tested with both kits. There was one false-positive reaction with both kits (0.4%) and one false-negative reaction only with the CDC kit, among 18 patients who had
meningitis or disseminated
infection due to Cryptococcus neoformans. Sera from patients who had localized pulmonary
cryptococcosis showed negative results with both kits. The
antigen titers measured by the two kits were the same or within two dilutions in 22 of 26 specimens of cerebrospinal fluid or serum from patients who had proved
cryptococcosis. Overall, the IBL kit compared favorably with the CDC kit for the detection of cryptococcal
antigen in cerebrospinal fluid or serum.