What diagnostic tests help confirm the presence of cryptococcal meningitis?

The CrAg test, or cryptococcal antigen test, along with India ink preparation, are the primary diagnostic tools used to confirm the presence of cryptococcal meningitis. The CrAg test is highly sensitive and specific for cryptococcal infection, especially useful in patients with HIV/AIDS, where the risk for opportunistic infections like cryptococcosis is elevated. A positive result indicates a significant fungal load and suggests the presence of cryptococcal meningitis.

The India ink preparation involves mixing a specimen of cerebrospinal fluid (CSF) with India ink on a slide and examining it under a microscope. This method allows for the visualization of encapsulated yeast cells, which are characteristic of Cryptococcus neoformans, the causative agent of cryptococcal meningitis.

In contrast, other tests do not specifically diagnose cryptococcal meningitis. PCR for viral RNA is utilized for diagnosing viral infections but does not pertain to fungal pathogens like Cryptococcus. Blood cultures can identify systemic infections but are less sensitive for cryptococcal disease compared to the antigen tests for CSF. Cerebellar function tests assess neurological function but are not diagnostic for cryptococcal meningitis, providing no information about the presence of Cryptococcus in the CSF or