Rapid diagnosis of cryptococcal meningitis by microscopic examination of centrifuged cerebrospinal fluid sediment

The classic India ink test is positive in only half of cryptococcal meningi tis cases, and reliable, rapid cryptosoccal antigen (CRAG) testing requires technical expertise and facilities not always available. We therefore exam ined cerebrospinal fluid (CSF) sediment using May-Giemsa, periodic acid-Sch iff, and Gram stains in 16 patients with cryptococcal meningitis. The India . ink test was positive in seven patients (44%), while microscopic examinat ion of sediment revealed cryptococci in 13 (81%), in six of these 13 the In dia ink test was negative. Both methods failed to detect the pathogen in th e remaining three patients. CRAG testing in CSF was negative in two patient s (one with aquired immunodeficiency syndrome, one with diabetes mellitus) whose India ink test also was negative while cryptococci were identified in their CSF sediment. No false positives occurred with CSF May-Giemsa staini ng in 27 cases of aseptic meningitis with negative cultures for Cryptococcu s. In all, microscopic examination of centrifuged and stained CSF sediment proved more sensitive for rapid diagnosis of cryptococcal meningitis than t he India ink method, and in two of our patients cryptococci were seen in ce ntrifuged CSF sediment despite negative CRAG and India ink tests. (C) 1999 Elsevier Science B.V. All rights reserved.