The leukocyte esterase test for detection of cerebrospinal fluid leukocytosis and bacterial meningitis.

We conducted a study to assess the efficacy of the dipstick leukocyte esterase test (LET) in the detection of cerebrospinal fluid (CSF) leukocytosis as a quick screen for bacterial meningitis. Nine hundred forty-two CSF samples were collected from 800 patients. The LET was compared in a double-blinded fashion with routine cell count determinations and cultures. We reviewed the clinical courses of all patients with positive cultures to assess the significance of culture isolates. Statistical analysis revealed LET sensitivity of 84.4% and specificity of 98.1% for clinical presentations of bacterial meningitis for which initiation of therapy is currently recommended. The LET identified culture-proven cases of meningitis with sensitivity of 73% and specificity of 95%. We propose the LET as an adjunct to, but not a replacement for, CSF cell count and chemistry determination in the initial laboratory assessment of bacterial meningitis. It is a reasonable screen that allows rapid initiation of treatment and directs the laboratory technician to devote extra attention to examination of a CSF specimen with a higher likelihood of pathology.