White Blood Cell Differential in Cerebrospinal Fluid (CSF)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like headaches, neck stiffness, fever, confusion, or neurological issues. It’s often used to investigate conditions such as meningitis, encephalitis, or other infections, as well as certain types of brain swelling or tumors.

What to Expect Before the Test

You’ll likely have a lumbar puncture (spinal tap) to collect a small amount of CSF. This procedure involves inserting a needle into your lower back. You may feel pressure or discomfort, but it’s usually brief. No special preparation is needed, but inform your provider about any medications you’re taking.

What the Test Results Mean

The test looks at different types of white blood cells (neutrophils, lymphocytes, monocytes, etc.) in the CSF. Abnormal counts or patterns can indicate infections, autoimmune diseases, or other neurological conditions. Your provider will interpret results in relation to your symptoms and overall health.

Common Conditions Monitored

This test is critical for diagnosing infections like bacterial or viral meningitis, inflammatory diseases such as multiple sclerosis, or conditions causing increased pressure in the brain (e.g., idiopathic intracranial hypertension). It can also help rule out other causes of neurological symptoms.