Investigations

Send CSF for: 

• Gram stain and cell count ^c

Note:

Bacterial meningitis is most commonly found on CSF Gram stains

% of positive CSF Gram stains	% (95% CI)
bacterial meningitis c	71% (65% to 77%)
viral meningitis	1.0% (0.0% to 2.3%)

CSF leukocyte counts in bacterial meningitis are higher than in viral meningitis (1.2 x 10 ⁹ /l compared with 0.1 x 10 ⁹ /l). ^c