Lymphocyte Count in Cerebrospinal Fluid (CSF)

What Is a CSF Lymphocyte Count Used For?

A CSF lymphocyte count is often used to evaluate conditions that cause inflammation or infection in the brain and spinal cord. It may be part of a broader evaluation for meningitis, encephalitis, multiple sclerosis, or other neurological disorders. Doctors may also check this test if you have symptoms like headaches, fever, confusion, or neurological problems that suggest an underlying issue in the central nervous system.

When Might You Need This Test?

Your healthcare provider might recommend a CSF lymphocyte count if you have symptoms such as persistent headaches, fever, stiff neck, seizures, confusion, or vision changes. It’s also used in diagnosing conditions like Guillain-Barré syndrome, Lyme disease, or certain types of brain tumors. Sometimes, it’s part of a routine checkup for people with known neurological conditions.

How Is the Test Performed?

The test involves a procedure called a lumbar puncture (spinal tap). A needle is carefully inserted into your lower back to collect a small amount of CSF. The sample is then analyzed in a lab to count the lymphocytes among other cells and substances in the fluid.

What Are Possible Results?

Results can vary widely depending on the reason for testing and your overall health. A high lymphocyte count in CSF may suggest an inflammatory or infectious process, while a normal count might indicate no immediate concern. Your doctor will interpret the results in the context of your symptoms and medical history.