Detection of cryptococcal antigens in serum or CSF is useful in the diagnosis of meningitis associated with infection by Cryptococcus neoformans. Commercially available latex agglutination test kits for the detection of Cryptococcal antigen have demonstrated cross-reactivity with syneresis fluid, rheumatoid factor, and the yeast Trichosporon beigelii, resulting in false positive test results. A new enzyme immunoassay (EIA) kit (Premier, manufactured by Meridian Diagnostics, Cincinnati, OH) for cryptococcal antigen determination is now available, and early studies indicate its comparability to the latex test. This EIA is currently being evaluated in parallel with the latex test to determine its cross-reactivity with specimens having high rheumatoid titers, specimens containing Trichosporon beigelii antigen, and samples containing syneresis fluid.
