False-positive culture results from patient tissue specimens due to contamination of RPMI medium with Cryptococcus albidus.

Cryptococcus albidus, a rare opportunist, was isolated from biopsy specimens from three patients over 4 days. An investigation showed that the specimens had been contaminated by placement in RPMI medium. The importance of rapid communication between the microbiology laboratory, the infectious diseases/infection control division, and other involved parties in the event of unusual occurrences is highlighted.