Multivariate logistic regression showed that four variables (S–PCT, CSF lactate ≥33 mg/dL, CSF glucose <60% of blood value, and CSF polymorphonuclears ≥50%) were excellent tools for the prediction of bacterial meningitis; the model using S–PCT ≥0.8 ng/mL and CSF lactate ≥33 mg/dL had an AUC of 0.992, with a 99% sensitivity and a 98% specificity for predicting bacterial meningitis (95% CI: 0.979–1; p < 001) [28]. This evidence concerns the gene CALCA and bacterial meningitis.