ABSTRACT
Cryptococcus neoformans is an encapsulated yeast that can cause life-threatening infectious diseases in both apparently immunocompetent and immunocompromised hosts in all areas of the world. This pathogenic yeast consists of four serotypes based on capsular agglutination reactions and three varieties or subspecies. Direct microscopic examination for the presence of encapsulated yeasts using India ink preparation of cerebrospinal fluid is a basic and useful rapid diagnostic test for cryptococcal meningitis. This technique can be performed within a few minutes after a lumber puncture and provides a presumptive diagnosis as well as other important information for clinicians, including identification of patients at high risk for failure due to a heavy fungal burden. C. neoformans, with its prominent capsule, can be prominently identified by histological stains of tissues from lungs, skin, bone marrow, brain, or other organs. Diagnosis of cryptococcosis has been significantly improved over the last several decades by the development of serological tests for cryptococcal polysaccharide antigen and/or antibody.
