Diagnostic accuracy of cerebrospinal fluid procalcitonin in bacterial meningitis patients with empiric antibiotic pretreatment

Accurate diagnosis of bacterial meningitis (BM) relies on cerebrospinal fluid (CSF) Gram staining and bacterial culture, which often present high falsenegative rates because of antibiotic abuse. Thus, a novel and reliable diagnostic biomarker is required. Procalcitonin (PCT) has been well demonstrated to be specifically produced from peripheral tissues by bacterial infection, which makes it a potential diagnostic biomarker candidate. Here, we performed a prospective clinical study comprising a total of 143 patients to investigate the diagnostic value of CSF PCT, serum PCT, and other conventional biomarkers for BM. Patients were assigned to the BM (n β 49), tuberculous meningitis (TBM) (n β 25), viral meningitis/encephalitis (VM/E) (n β 34), autoimmune encephalitis (AIE) (n β 15), or noninflammatory nervous system diseases (NINSD) group (n β 20). Empirical antibiotic pretreatment was not an exclusion criterion. Our results show that the CSF PCT level was significantly (P - 0.01) higher in patients with BM (median, 0.22 ng/ml; range, 0.13 to 0.54 ng/ ml) than in those with TBM (median, 0.12 ng/ml; range, 0.07 to 0.16 ng/ml), VM/E (median, 0.09 ng/ml; range, 0.07 to 0.11 ng/ml), AIE (median, 0.06 ng/ml; range, 0.05 to 0.10 ng/ml), or NINSD (median, 0.07 ng/ml; range, 0.06 to 0.08 ng/ml). Among the assessed biomarkers, CSF PCT exhibited the largest area under the receiver operating characteristic curve (0.881; 95% confidence interval, 0.810 to 0.932; cutoff value, 0.15 ng/ml; sensitivity, 69.39%; specificity, 91.49%). Our study sheds light upon the diagnostic dilemma of BM due to antibiotic abuse. (This study has been registered at ClinicalTrials.gov under registration no. NCT02278016.).