CALCA and viral meningitis: [18] Gendrel et al. have demonstrated elevated PCT levels (mean level, 54.5 mg/L; range, 4.8–110 mg/L) in bacterial meningitis while low levels (mean level, 0.32 mg/L; range, 0–1.7 mg/L; P. .0001) in viral meningitis in children when there is zone of overlapping values in CSF cells and proteins and CRP [9, 16].