| Bacterial meningitis | Viral meningitis | 
|---|
| Hundreds (or even thousands) of inflammatory cells × 106 /l | Inflammatory cell count up to 200 × 106 /l | 
| Nearly all inflammatory cells polymorphonuclear | Inflammatory cells mononuclear (at the beginning of the disease most of them may be polymorphonuclear) | 
| Glucose concentration low (< 2.2 mmol/l or < half of blood glucose) | Glucose concentration normal (> 2.2 mmol/l) | 
| Protein concentration high (> 400 mg/l, typically > 1 000 mg/l) | Protein concentration only slightly elevated | 
| Gram-staining shows bacteria | Gram-staining does not show bacteria | 
| Lactate concentration high (> 2.7 mmol/l) | Lactate concentration normal |