The utility of cerebrospinal fluid parameters in the early microbiological assessment of meningitis

The measurement of cerebrospinal fluid (CSF) protein, glucose, and white cell count (WCC) is an essential part of the initial examination of CSF. The aim of this study was to determine the utility of CSF parameters in assessing the likely aetiological agent. A total of 2290 CSF samples from a 13-year period were retrospectively reviewed. The initial parameters were compared between bacterial, viral, and cryptococcal meningitis and cases where no pathogen was found. A protein concentration of <600 mg/L and a WCC <90 × 106/L were found to be optimal cut-offs for excluding bacterial meningitis. A WCC of <25 × 106/L was found to be optimal for excluding cryptococcal meningitis and a WCC of <10 × 106 for excluding viral meningitis. Decreased glucose concentration was found to be a poor indicator of the aetiological agent.