Diagnostic value of cerebrospinal fluid Neutrophil Gelatinase-Associated Lipocalin for differentiation of bacterial meningitis from tuberculous meningitis or cryptococcal meningitis: a prospective cohort study

Abstract

Background The early differential diagnosis between bacterial meningitis (BM) and tuberculous meningitis (TBM) or cryptococcal meningitis (CM) is still an important clinical challenge. Neutrophil Gelatinase-Associated Lipocalin (NGAL) had been reported as a novel inflammatory biomarker in early stage of infection. This study aimed to explore whether cerebrospinal fluid (CSF) NGAL is a potential biomarker for distinguishing between BM and TBM or CM. Methods Prospectively enrolled the patients with suspected CNS infections at admission and divided them into three case groups: BM (n = 67), TBM (n = 55), CM (n = 51), and an age- and sex-matched hospitalized control (HC, n = 58). Detect the CSF NGAL and evaluate the diagnostic accuracy to distinguish between BM and TBM or CM. Meanwhile, longitudinally measured the CSF NGAL of BM to evaluate whether it would be a monitor of antibacterial treatment. Results The CSF NGAL in BM was significantly higher than in TBM, CM and HC (all P < 0.05), while the serum NGAL was not significantly different among the three case groups. The ROC analysis showed CSF NGAL presented a good diagnostic performance with an AUC of 0.834 (0.770 to 0.886) and at the optimal cutoff value of 74.27 ng/mL with 70.15% sensitivity and 77.36% specificity for discriminating BM with TBM and CM. Meanwhile, the CSF NGAL in the convalescent period of BM was significantly lower than the acute period (P < 0.05). Conclusions CSF NGAL might be a potential biomarker for distinguishing between acute BM and TBM or CM, and it also has some important clinical value for monitoring antibiotic therapy for BM.