Definition

CSF myelin basic protein is a test to measure the level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF).

CSF is a clear liquid that surrounds the brain and spinal cord.

MBP is found in the material that covers many of your nerves.

How the Test is Performed

A sample of spinal fluid is needed. This is done using a lumbar puncture.

Why the Test is Performed

This test is done to see if myelin is breaking down. Multiple sclerosis is the most common cause for this, but other causes may include:

• Bleeding of the central nervous system
• Central nervous system trauma
• Certain brain diseases (encephalopathies)
• Infection of the central nervous system
• Stroke
• Traumatic brain injury

Normal Results

In general, there should be less than 4 ng/mL of myelin basic protein in the CSF.

Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.

The example above shows the common measurement result for this test. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

Myelin basic protein levels from 4 to 8 ng/mL may be a sign of a long-term (chronic) breakdown of myelin. It may also indicate recovery from an acute episode of myelin breakdown.

If the myelin basic protein level is 9 ng/mL or greater, myelin is actively breaking down.

References

Euerle BD. Spinal puncture and cerebrospinal fluid examination. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 60.

Fabian MT, Krieger SC, Lublin FD. Multiple sclerosis and other inflammatory demyelinating diseases of the central nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022: chap 80.

Karcher DS, McPherson RA. Cerebrospinal, synovial, serous body fluids, and alternative specimens. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 30.