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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.
See also:
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
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 Results
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
Risks
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.
Rosenberg GA. Brain edema and disorders of cerebrospinal fluid circulation. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 63.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Kevin Sheth, MD, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
