White Blood Cell Count in Cerebrospinal Fluid (CSF)

Why This Test Is Done

Your doctor may order this test if you have symptoms like headaches, neck stiffness, fever, confusion, or neurological issues that could indicate an infection (such as meningitis), inflammation, or other conditions affecting the brain or spinal cord. It’s often done alongside other tests, like a lumbar puncture, to guide treatment decisions.

What to Expect Before the Test

No special preparation is needed. The test involves a small sample of CSF collected through a procedure called a lumbar puncture (spinal tap). You may feel mild discomfort during the procedure, but it’s usually brief. Avoid alcohol or certain medications that could affect test results for 24 hours before the test.

What Happens During the Test

A healthcare provider will insert a needle into your lower back to collect CSF. The sample is then sent to a lab for analysis, including counting white blood cells. The test typically takes a few minutes, and you’ll be monitored for any complications.

What the Results Mean

Results are reported as the number of white blood cells per microliter (cells/µL) of CSF. While reference ranges vary by lab, elevated counts may suggest infection (e.g., bacterial or viral meningitis), inflammation, or other conditions like multiple sclerosis. Lower-than-expected counts could indicate bleeding or other rare issues.