"False negative" CSF cryptococcal antigen with clinical meningitis: Case reports and review of literature.

There is an increasing recognition of patients presenting with cryptococcal meningitis despite having a negative CSF cryptococcal antigen (CrAg). In this report, we describe three cases of patients with advanced immunosuppression who presented to hospital with "false negative" CSF cryptococcal antigen, two of whom had a positive fungal culture. We describe the challenge of CSF-CrAg negative cryptococcal meningitis and explore ways to overcome this challenge using newer diagnostic techniques.