CSF oligoclonal banding

Definition

This is a test performed on cerebrospinal fluid (CSF), the clear fluid that circulates in the space surrounding the spinal cord and brain. The CSF contains substances that may be markers for disease.

Oligoclonal bands are immunoglobulins that suggest inflammation of the central nervous system. The presence of oligoclonal bands may be a sign of multiple sclerosis.

How the test is performed

A lumbar puncture (spinal tap) is performed and the fluid is sent to the laboratory for analysis.

How the test will feel

Patients will be asked to either sit up or lie down on their side with back parallel to the bed and chin tucked under and legs curled in the fetal position. The healthcare provider will use the bony protrusions of the hip to determine the most appropriate location to remove fluid. This is usually at the L3-L4 vertebral level.

Subsequently iodine will be used to clean off the area and a sterile sheet will be draped over the surrounding area. In infants and small children, a local anesthetic cream to numb the skin, will be applied about 1 hour prior to the procedure. In adults, lidocaine will be injected under the skin initially, and then deeper such that tissue beneath the skin will also be numbed.

A thin, 20-gauge needle will then be inserted into the interspace between the vertebra. Depending on how much subcutaneous tissue there is, this may require shallow or deeper penetration of the needle. There may be an audible pop when the needle penetrates the dura (membrane surrounding the spinal cord and encasing the fluid).

At this point, fluid will flow out of the needle and be collected in plastic containers. Under normal circumstances, the opening pressure will be measured with a manometer and then about 20-30 cc of spinal fluid will be collected and sent for evaluation under the microscope.

Under experienced hands there should not be any pain. There may be a feeling of pressure when the needle is inserted but with appropriate anesthetic, this should not hurt. Occasionally, some people may feel numbness shooting down the leg. This may be due to irritation of a nerve root and subsides when the needle is withdrawn.

Following the procedure, the patient is advised to remain lying down for an hour or two to prevent low-pressure headache. The entire procedure takes approximately 20 minutes.

Why the test is performed

This test helps support, but does not confirm, the diagnosis of multiple sclerosis (MS). The presence of oligoclonal bands in the CSF must be interpreted in the context of clinical findings and other laboratory results.

Normal Values

Negative result -- one or less bandings found in the CSF is normal.

What abnormal results mean

The test results are positive. There are 2 or more bandings found in the CSF and not in the blood serum. This may indicate multiple sclerosis.

What the risks are

• Risks of lumbar puncture include:
  • hypersensitivity (allergic) reaction to the anesthetic
  • discomfort during the test
  • headache after the test
  • bleeding into the spinal canal
• Brain herniation (if performed on a person with increased intracranial pressure), resulting in brain damage and/or death
• Damage to the spinal cord does not occur because the needle is inserted below the level at which the spinal cord ends. The needle may irritate a nerve root which results in transient numbness or tingling in the leg. This goes away when the needle is re-adjusted.

Special considerations

To confirm multiple sclerosis, clinical symptoms and consistent MRI findings must also be present.

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Cerebrospinal fluid - immunofixation