Glucose in Cerebrospinal Fluid (CSF)

Why Is This Test Done?

Doctors may order a CSF glucose test if you have symptoms like severe headaches, neck stiffness, fever, confusion, or signs of a brain infection (meningitis), a brain bleed, or other neurological conditions. It can also be part of a diagnostic workup for conditions like multiple sclerosis or other spinal issues.

What Does a Low or High CSF Glucose Level Mean?

Low CSF glucose levels (often seen in bacterial meningitis or brain abscesses) suggest an infection or inflammation disrupting blood flow to the brain. High levels may occur in viral meningitis or other conditions affecting the brain’s blood supply, though this is less common.

How Is the Test Performed?

A sample of your cerebrospinal fluid is collected through a procedure called a lumbar puncture (spinal tap). A needle is gently inserted into your lower back to draw fluid into a vial. The test is usually done in a lab to measure glucose levels using an enzymatic method.

What Are Common Causes of Abnormal Results?

Abnormal CSF glucose results can occur due to infections (bacterial vs. viral meningitis), brain tumors, multiple sclerosis, or conditions affecting blood flow to the brain. Always discuss results with your healthcare provider, as they’ll consider your full medical history and symptoms.