Cerebrospinal Fluid Analysis

Analyte/characteristics

Reference range/normal appearance

Result interpretation: meningitis

Purulent

Viral

Tuberculous

Appearance

Colorless, clear

Yellowish, turbid

Colorless, clear

Opalescent, clear, cobweb-like coagulum may be found

Cell count

≤0.005×109/L (100% lymphocytes)

>1 up to total HPF coverage (95%-100% neutrophilsa)

>1 to >100 (0%-25% neutrophils,b >75% lymphocytes)

>20-1000 (0%-25% neutrophils, >75% lymphocytes)

Protein

0.15-0.45 g/L (15-45 mg/dL)

>2 g/L

↑ (<2 g/L)

Usually ~1 g/Lc

Glucose (% of plasma)

60-75

↓↓↓ (very low)

N or ↓

↓↓ (10-30)

Chlorides

>117 mmol/L

↓↓

N or ↓

Often ↓↓

Lactic acid

<2.1 mmol/L

↑↑↑

N or ↑ (2.2-3 mmol/L)

↑↑ (>3.5 mmol/L)

a The percentage of neutrophils in meningitis caused by Listeria monocytogenes infection may be slightly lower (>75%).

b Neutrophils are more prevalent (>60%) in enteroviral meningitis (caused by ECHO and Coxsackie viruses) within 48 hours of infection onset.

c Up to >20 g/L in myelitis.