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CSF – Microscopy and Culture



Analysis of CSF for bacterial infection:

  • Microscopy – cell count (& gram stain if needed)
  • Culture

Click here for CSF Viral PCR


Diagnosis of meningitis / encephalitis


Cerebrospinal fluid (CSF)

Specimen container

Sterile white top universal pot

How To Request On EPIC

For electronic requesting using EPIC (RDUH ONLY):

Search for: ‘CSF MC&S‘ or test code ‘LAB212

Special Instructions

Please send first and third specimens to Microbiology (Clearly label each container)

Gram stains will only be performed if there is a raised white blood cell count – outside of the normal range (see table below.)

Transport to the laboratory

Specimens where possible should be taken prior to commencement of antibiotic therapy, and should reach microbiology within 2 hours. Do not refrigerate specimen until after microscopy and bacterial culture have been performed.

If you are taking an urgent CSF out of hours – please call a porter for immediate transport to the laboratory and contact the On Call Microbiology Biomedical Scientist through the hospital switchboard for urgent microscopy.

Samples taken after 4am will be processed at 8am if labelled “urgent”, and need not be telephoned.


Processed locally in Microbiology at RDUH

Turnaround Time

Microscopy 24hrs

Culture 48hrs (Negative result)

Urgent Specimen Instructions

Please phone the laboratory if urgent microscopy results are required (except between 4am and 8am).

Biological Reference Interval

Cell Count – Normal CSF Values

Cell Type Age Group Age Range Normal Range
Leucocytes (White Blood Cells)




Less than 28 days old

1 to 12 months old

1 year old +

0-30 cells x 106/L

0-15 cells x 106/L

0-5 cells x 106/L

 Erythrocytes (Red Blood Cells) All All No RBCs should be present in normal CSF

Useful Links


CSF Analysis – Lab Tests Online

Meningitis and Encephalitis – Lab Tests Online

Meningitis – NHS

Encephalitis – NHS

For Healthcare Professionals:

SMI – S 5 – Meningoencephalitis (rcpath.org)

SMI – B 27 – Investigation of Cerebrospinal Fluid (rcpath.org)


Specimen Labelling Procedure
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