Diagnostic Accuracy of Cerebrospinal Fluid Neutrophil Gelatinase-Associated Lipocalin in Patients with Acute Bacterial Meningitis: A Prospective Cohort Study

Background: It is difficult for early differential diagnosis between bacterial meningitis (BM) and tuberculous meningitis (TBM) or cryptococcal meningitis (CM).Therefore, a novel and reliable biomarker is urgently required. Neutrophil Gelatinase-Associated Lipocalin (NGAL) have been reported as a novel biomarker for differentiating the bacterial or viral infections, however, whether the CSF NGAL is a potential biomarker for distinguishing between BM and TBM or CM are not reported. Methods: Prospectively enrolled the patients with suspected CNS infections at admission, and divided them into three case groups: BM (n=47), TBM (n=34), CM (n=30), and a hospitalized control (HC, n=39). Detected 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 the antibacterial treatment.  Results: The CSF NGAL in BM was significantly higher than TBM, CM and HC, and the serum NGAL was not significantly different among three case groups. The ROC analysis showed that CSF NGAL presented a good diagnostic performance with an AUC of 0.907(95% CI: 0.830 to 0.985), and at the optimal cutoff value of 16.55 ng/mL with 88.46% sensitivity and 81.25% specificity for discriminating BM from TBM or CM. Meanwhile, the CSF NGAL in convalescent period of BM was significantly lower than the acute period. Conclusion: CSF NGAL could be used as an early diagnostic biomarker of BM, especially when compared with TBM or CM, and it also might be have some important clinical value for monitoring antibiotic therapy of BM. Funding Statement: The study was supported in part by the grants from the National Natural Science Foundation of China (No.81802088), the Joint Funds for the innovation of science and Technology, Fujian Province (No.2018Y9080), the Natural Science Foundation of Fujian Province (No.2016J05185), and the Youth Foundation of Health and Family Planning Commission of Fujian Province (No.2016-1-55). Declaration of Interests: The authors: No reported conflicts of interest. Ethics Approval Statement: The study protocol was approved by the Institutional Review Board of the First Affiliated Hospital of Fujian Medical University. Written informed consent was obtained from the participants or their surrogates prior to the study.