LACTATE ASSAY IN CEREBROSPINAL-FLUID FOR DIAGNOSIS OF BACTERIAL-MENINGITIS - STRATEGIES FOR DETERMINING A DISCRIMINATORY THRESHOLD

OBJECTIVES: In search for a supplementary marker of baterial meningiti s in cases where conventional bacteriology, cytology and chemistry are insufficiently contributive to diagnosis, we assessed the value of cr ebrospinal fluid lactate levels in children with bacterial meningitis. PATIENTS AND METHODS: Cerebrospinal fluid lactate levels were measure d from all spinal taps performed in a pediatric emergency care unit ov er a two-year period. Of the 332 usable samples there were 32 cases of bacterial meningitis, 104 cases of viral meningitis and 196 other dia gnoses (nan meningitis) RESULTS: Average lactate concentration 7+/-4 m mol/l in bacterial meningitis versus 2.1+/-0.6 mmol/l in viral meningi tis (p <0.0001). The value of lactic add concentrations in discriminat ing between bacterial and viral meningitis was found to be superior to that of other chemistry results : protein, glucose, chloride. The dis criminatory thereshold of cerebrospinal fluid lactate was 3.7 mmol/l w ith sensitivity of 80% and a specificity of 98%. CONCLUSION: We propos e routine assay of cerebrospinal fluid lactate in all cases of suspect ed meningitis.