Evaluation of the cryptococcal antigen test as a diagnostic tool of AIDS-associated cryptococcosis in Rwanda

To evaluate the latex test, two different retrospective studies were undertaken. A positive culture for Cr. neoformans was used as the golden standard of active cryptococcal infection. 439 sera selected at random sent to the NSP laboratory for screening of HIV antibody were tested as well as--71 CSF from patients with meningeal symptoms sent to the laboratory of the Centre Hospitalier de Kigali. In total, two discrepancies were found: two CSF samples from ancient cases of cryptococcosis under treatment were positive with the latex test and negative by culture. If it stands to reason that the antigen test cannot differentiate between active and inactive cryptococcal diseases, the persistence of small amounts of soluble antigens in a CSF implies that the patient must remain under surveillance, a relapse being very frequent in AIDS patients. As a conclusion, the latex test is a fast, easy to perform and quite reliable test for the diagnosis of cryptococcosis.