Correlation between serum cryptococcal antigen titre and meningitis in immunocompetent patients.

The aim of this paper was to determine the correlation between serum cryptococcal antigen and a diagnosis of cryptococcal meningitis in the immunocompetent cohort. A retrospective multicentre analysis of immunocompetent patients diagnosed and treated for cryptococcal meningitis between January 2000 and December 2017 was performed. Sixty-seven of the 143 cases of cryptococcosis occurred in immunocompetent patients. The serum cryptococcal antigen titre was significantly higher in the meningitis group [1 : 256 (IQR: 64-1024)] compared with that for non-meningitis patients [1 : 64 (IQR: 8-256)], P=0.012. The relative risk of meningitis with a serum cryptococcal antigen (CRAG) >1 : 64 was 1.8 (95 % CI: 1.15-2.82). This study demonstrates a clear correlation between serum cryptococcal antigen titre and meningitis. While the serum titre is not definitive for meningitis, in resource-limited settings or cases where lumbar puncture may be contraindicated, this evidence may aid diagnosis and subsequent therapeutic decisions.