Average PCT concentrations in CSF were 0.60 ng mL−1 (95% CI: 0.29–0.92) in the bacterial meningitis group (n = 26), 0.81 (95% CI: 0.33–1.28) in community‐acquired meningitis (n = 16) and 0.28 (95% CI: 0.10–0.45) in postneurosurgical meningitis (n = 10), 0.10 ng mL−1 (95% CI: 0.08–0.12) in the viral meningitis group (n = 14) and 0.08 ng mL−1 (95% CI: 0.06–0.09) in the noninfectious group (n = 14). The gene discussed is CALCA; the disease is bacterial meningitis.