In this section
Meningitis Lumbar Puncture
This guideline is to help with the interpretation of CSF results for the purpose of diagnosing or excluding meningitis. The use of CSF for other purposes (including the diagnosis of specific neurological conditions, subarachnoid haemorrhage or malignancy) is outside the scope of this guideline.
White cell count
Biochemistry
Neutrophils
(x 106 /L)
Lymphocytes
(x 106/L)
Protein
(g/L)
Glucose
(CSF:blood ratio)
Normal
(>1 month of age)
0
≤ 5
< 0.4
≥ 0.6 (or ≥ 2.5 mmol/L)
Normal neonate
( <1 month of age)
< 20
<1.0
The presence of any neutrophils in the CSF is unusual in normal children and should raise concern about bacterial meningitis
Meningitis can occur in children with normal CSF microscopy.
If it is clinically indicated, children who have a 'normal' CSF should still be treated with IV antibiotics pending cultures.
CSF white cell count and protein level are higher at birth than in later infancy and fall fairly rapidly in the first 2 weeks of life. In the first week, 90% of normal neonates have a white cell count less than 18, and a protein level < 1.0 g/L.
Normal term
neonate
0*
< 1.0
Bacterial meningitis
100-10,000
(but may be normal)
Usually < 100
> 1.0
Viral meningitis
Usually <100
10-1000
0.4-1
Usually normal
TB meningitis
50-1000
1-5
< 0.3
* Some studies have found up to 5% of white cells in neonates without meningitis comprise neutrophils