Background: In adults, procalcitonin (PCT) has been the focus of various investigations about its diagnostic accuracy in differentiating between bacterial and aseptic meningitis in adults. This study set out to determine whether procalcitonin is a good diagnostic tool for distinguishing between bacterial and non-bacterial meningitis.

Methods: We performed a cross-sectional study with 32 patients: 16 in Group A, who had bacterial meningitis (ascertained by positive cerebrospinal fluid culture and/or Gram stain), and 16 in Group B, who had aseptic meningitis (ascertained by negative cerebrospinal fluid culture and Gram stain). We measured CSF procalcitonin, C-reactive protein (CRP), blood glucose, and complete blood counts (CBCs) before antibiotic treatment began.

Results: A CSF procalcitonin cutoff of 0.5 ng/mL demonstrated excellent diagnostic accuracy, with 87.5% sensitivity and 93.75% specificity (AUC 0.887) in distinguishing between the two groups. Several inflammatory indicators were positively correlated with CSF procalcitonin levels. On the other hand, insulin levels (r=-0.622, p<0.001) and the number of lymphocytes (r=-0.766, p<0.001) were inversely associated with CSF procalcitonin levels. In a multivariate linear regression analysis that considered other variables, CSF procalcitonin remained strongly associated with TLC (β=0.128, p<0.001), CRP (β=0.012, p=0.04), and neutrophil count (β=0.056, p=0.02).

Conclusion:

This study demonstrates that cerebrospinal fluid procalcitonin is a reliable and highly accurate biomarker for distinguishing bacterial meningitis from aseptic meningitis in adults. With a diagnostic cutoff value of 0.5 ng/mL, CSF procalcitonin exhibited 87.5% sensitivity and 93.75% specificity, underscoring its utility as a rapid and effective diagnostic tool.