The clinical laboratory evaluation of cryptococcal infections in the acquired immunodeficiency syndrome.

The medical and laboratory records were reviewed in 37 acquired immunodeficiency syndrome (AIDS) patients with cryptococcal infections. In 24 patients with the presentation of cryptococcal meningitis, the initial cerebrospinal fluid (CSF) culture was positive. The initial India ink mount demonstrated organisms in 79% of culture positive CSF specimens. After therapy the subsequent India ink mounts demonstrated 84% sensitivity and 53% specificity with respect to culture outcome. Cultures of blood, bronchoalveolar lavage fluid, and brain were more likely to be positive than cultures from other sites. The initial blood cultures were positive in eight of eight patients at presentation of cryptococcal meningitis. When the initial CSF titer was greater than 1:2, the corresponding CSF culture was always positive. A negative culture during therapy did not necessarily indicate eradication of infection. The initial cerebrospinal fluid and serum cryptococcal antigen titers varied significantly and could not be correlated with survival. In three instances when the CSF cryptococcal antigen titers and cultures were negative, a positive serum cryptococcal antigen greater than 1:8 suggested disseminated infection.