Rapid diagnosis of meningitis with use of selected clinical data and gas-liquid chromatographic determination of lactate concentration in cerebrospinal fluid.

The usefulness of determination of lactate concentration in cerebrospinal fluid (CSF) for differentiation between various types of meningitis was evaluated. Lactate concentration in the CSF was assayed by gas-liquid chromatography for 115 patients, 17 of whom had serous meningitis and 38 had bacterial meningitis. The mean lactate concentration in the CSF of patients with bacterial meningitis was significantly higher than in the CSF of patients with serous meningitis and in a control group. The mean concentration in patients with serous meningitis was significantly higher than in controls. The highest lactate level in serous meningitis overlapped with the lowest level in bacterial meningitis. Elevated lactate concentrations in CSF were found also in patients with noninfectious disorders of the central nervous system. Misleading results may therefore be obtained if the lactate concentration in CSF alone is used to distinguish between serous and bacterial meningitis. The study suggests, however, that measurements of lactate levels in CSF, when combined with clinical and conventional laboratory observations, can increase the reliability of rapid diagnosis of bacterial meningitis.