Diagnostic Test Accuracy of Serum and Cerebrospinal Fluid C-Reactive Protein in Bacterial Meningitis: A Systematic Review and Meta-Analysis.

Background: Bacterial meningitis is a serious infection leading to increased morbidity and mortality every year due to delayed diagnosis and treatment. Previous literatures had shown that cerebrospinal fluid (CSF) procalcitonin outweighs serum procalcitonin to diagnose bacterial infections of the central nervous system (CNS). Current meta-analysis aims to find the diagnostic accuracy of serum and CSF C-reactive protein (CRP) to diagnose bacterial meningitis.

Material and methods: PubMed, Google Scholar, Cochrane Library and Google databases were searched from 1st January 1980 to 30th June 2022. Observational studies, prospective or retrospective focusing on C-reactive protein as a biomarker for bacterial meningitis in adult patients were searched. The articles related to serum and CSF CRP for diagnosing bacterial meningitis were explored and retrieved separately, by two independent experts from the published studies available in the electronic search engines. The risk of bias and scholarly quality of studies were evaluated by QUADAS-2.

Results: Altogether 637 articles were recognized, out of which 22 studies selected. CSF CRP has shown better diagnostic value than serum CRP. Pooled sensitivity of CSF CRP was 0.89 (95% confidence interval [CI], 0.81-0.94), specificity 0.96 (95% CI, 0.92-0.97), area under the curve (AUC) 0.98 (95% CI, 0.96-0.99), diagnostic odds ratio (DOR) 175 (95% CI, 74-410), positive likelihood ratio (PLR) 20 (95% CI, 11.5-34.1) and negative likelihood ratio (NLR) 0.11 (95% CI, 0.06-0.21). While, pooled sensitivity of serum CRP was 0.80 (95% CI: 0.69-0.88), specificity 0.86 (95% CI, 0.74-0.93), AUC 0.89 (95% CI, 0.86-0.92), DOR 24 (95% CI, 9-62), PLR 6 (95% CI, 2.9-10.7) and NLR 0.23 (95% CI, 0.15-0.37). Heterogeneity was higher for serum CRP than CSF CRP.

Conclusion: Our meta-analysis shows that CSF CRP had higher pooled sensitivity, specificity and PLR along with higher AUC and DOR for confirming bacterial meningitis in adults than serum CRP.