Health Encyclopedia

CSF glucose test

Definition

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.

Alternative Names

Glucose test - CSF; Cerebrospinal fluid glucose test

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

After the sample is taken, it is sent to a laboratory for evaluatoin.

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.

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

References

Griggs RC, Jozefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 418.

Review Date:6/24/2009
Reviewed By:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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