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CSF total protein
Definition
CSF total protein is a test to determine the amount of protein in cerebrospinal fluid (CSF). CSF is a clear fluid that circulates in the space surrounding the spinal cord. An abnormal protein level in the CSF suggests that there is an abnormal process occurring in the central nervous system.
How the test is performed
A sample of CSF is needed. A lumbar puncture (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, by 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 evaluation.
How to prepare for the test
See: Lumbar puncture
How the test will feel
See: Lumbar puncture
Why the test is performed
Your doctor may order this test to help diagnose tumors, infection, inflammation of several groups of nerve cells, vasculitis, blood in the spinal fluid, or injury.
Normal Values
The normal protein range varies from lab to lab, but is typically about 15 to 60 mg/dL.
Note: mg/dL = milligrams per deciliter
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
When the protein level in the CSF increases considerably, it may be a sign of a tumor, bleeding, nerve inflammation, or injury.
When the protein level in the CSF decreases, it can mean your body is rapidly producing spinal fluid.
Protein can accumulate in the lower spinal area where the lumbar puncture is performed if the free flow along the spinal cord is blocked by something. In this case, the protein can be many hundreds of milligrams/deciliter.
Additional conditions under which the test may be performed:
- Hemorrhage - subarachnoid
- Neuropathy, including chronic inflammatory polyneuropathy
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.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.
