Definition of CSF glucose test:

A CSF glucose test measures the amount of sugar (glucose) in the cerebrospinal fluid (CSF). CSF is a clear fluid that flows in the space surrounding the spinal cord and brain.

See also:

• Glucose test - blood
• Glucose test - urine

How the test is performed:

A sample of CSF is needed. A lumbar puncture, also called a spinal tap, is the most common way to collect this sample. For information on this procedure, see the article on lumbar puncture.

Other methods for collecting CSF are rarely used, but may be recommended in some cases. They include:

• Cisternal puncture
• Ventricular puncture
• Removal of CSF from a tube that is already in the CSF, such as a shunt or ventricular drain

The sample is sent to a laboratory for testing.

How to prepare for the test:

See: Lumbar puncture

How the test will feel:

See: Lumbar puncture

Why the test is performed:

This test may be done to diagnose tumors, infections, inflammation of the central nervous system, delirium, and other neurological and medical conditions.

Normal Values:

The glucose level in the CSF should be 50 - 80 mg/100 mL (or greater than 2/3 of the blood sugar level).

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean:

Abnormal results include increased and decreased glucose levels. Abnormal results may be due to:

• Infection (bacterial or fungus)
• Inflammation of the central nervous system
• Tumor

What the risks are:

See: Lumbar puncture