Diagnostic accuracy of cerebrospinal fluid lactate for differentiating bacterial meningitis from aseptic meningitis: A meta-analysis

Objectives: Cerebrospinal fluid (CSF) lactate is produced by bacterial anaerobicmetabolism and is not affected by blood lactate concentration, an advantage over CSF glucosein differentiating bacterial meningitis from aseptic meningitis. However, the previous investi-gations have shown mixed results of the sensitivity and specificity. Our study's purpose was toassess the utility of CSF lactate in differentiating bacterial meningitis from aseptic meningitis.Methods: We searched MEDLINE and EMBASE for clinical studies that included CSF lactate mea-surement in bacterial meningitis and aseptic meningitis. Test characteristics were pooled usinghierarchical summary ROC curve and random effects model.Results: Thirty three studies were included. The pooled test characteristics of CSF lactatewere sensitivity 0.93 (95% CI: 0.89 e 0.96), specificity 0.96 (95% CI: 0.93 e 0.98), likelihood ratiopositive 22.9 (95% CI: 12.6 e 41.9), likelihood ratio negative 0.07 (95% CI: 0.05 e 0.12), and diag-nostic odds ratio 313 (95% CI: 141 e 698). Pretreatment with antibiotics lowered the sensitivity0.49 (95% CI: 0.23 e 0.75). CSF lactate of around 35 mg/dl (34 e 36 mg/dl) had higher sensitivityand specificity than those of around 27 mg/dl (26 e 28 mg/dl).Conclusions: CSFlactate's highnegative likelihoodratio may make it useful for rulingoutbacterialmeningitis though pretreatment with antibiotics reduces clinical accuracy. CSF lactate of 35 mg/dlcould be optimal cut-off value for distinguishing bacterial meningitis from aseptic meningitis.