Eosinophil count in cerebrospinal fluid (CSF)

What Is Eosinophil Count Used For?

Eosinophils are typically found in lower amounts in cerebrospinal fluid under normal conditions. When elevated, they may suggest conditions like parasitic infections, certain fungal infections, or inflammatory diseases such as sarcoidosis. This test helps doctors diagnose or monitor these conditions by examining fluid collected through a spinal tap.

When Might You Need This Test?

Your doctor may order this test if you have symptoms like severe headaches, neck stiffness, nausea, or if they suspect a condition affecting the central nervous system. It’s also used in cases where other tests or symptoms point toward eosinophilic meningitis or other eosinophil-related disorders.

How Is the Test Performed?

A small amount of cerebrospinal fluid is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then sent to a lab for analysis, where eosinophils are counted under a microscope.

What Are Possible Results?

Results are typically reported as the number of eosinophils per microliter (µL) of CSF. While specific reference ranges can vary, elevated counts (above normal baseline) are key to identifying potential issues.