Cerebrospinal Fluid Abnormalities in Bacterial Meningitis
| Opening pressure | >180 mmH2O |
| White blood cells | 10/µL to 10,000/µL; neutrophils predominate |
| Red blood cells | Absent in nontraumatic tap |
| Glucose | <2.2 mmol/L (<40 mg/dL) |
| CSF/serum glucose | <0.4 |
| Protein | >0.45 g/L (>45 mg/dL) |
| Gram's stain | Positive in >60% |
| Culture | Positive in >80% |
| Latex agglutination | May be positive in patients with meningitis due to Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b, Escherichia coli, group B streptococci |
| Limulus lysate | Positive in cases of gram-negative meningitis |
| PCR | Detects bacterial DNA |