Cerebrospinal fluid (CSF)

Suspected bacterial meningitis (infection within the sub-arachnoid space between the pia mater and arachnoid) should be confirmed by CSF culture unless LP is contraindicated. Please indicate where high risk organisms are implicated (such as TB).
Please number containers clearly (1,2,3 etc), tube 3 should be labelled for MC&S and will be used for the cell count. A high WBC count along with a positive Gram stain supports a diagnosis of bacterial meningitis, but a negative Gram stain does not exclude meningitis. Where subarachnoid bleed is suspected please send 3 tubes (numbered 1,2 & 3) so that comparison can be made between a traumatic tap and SAH. Microbiology will perform microscopy, isolation, identification and susceptibility of any organism likely to be pathogenic. Microscopy results are available within 4 hours of receipt of sample, negative culture results will be issued at 48 hrs, positive cultures 2-3 days.
Where possible, send separate tubes for separate tests as specimens may be processed for a wide range of tests in different departments including virology, cryptococcal Ag, AAFB, where clinically indicated. Likewise any specimens for cytopathological examination should be sent separately as MC&S will render specimens unusable for this. If Xanthachromia is required, send a tube to Reference Chemistry, this should be covered to avoid light damage.