Cerebral spinal fluid (CSF) collection

Definition

Cerebrospinal fluid (CSF) collection is a test to look at the fluid that surrounds the brain and spinal cord.

CSF acts as a cushion, protecting the brain and spine from injury. The fluid is normally clear. Ithas the same consistency as water. The test is also used to measure pressure in the spinal fluid.

How the Test is Performed

There are different ways to get a sample of CSF. Lumbar puncture (spinal tap) is the most common method.

To have the test:

Occasionally, special x-rays are used to help guide the needle into position. This is called fluoroscopy.

Lumbar puncture with fluid collection may also be part of other procedures such as an x-ray or CT scan after dye has been inserted into the CSF.

Rarely, other methods of CSF collection may be used.

CSF may also be collected from a tube that's already placed in the fluid, such as a shunt or a ventricular drain.

How to Prepare for the Test

You will need to give the health care team your consent before the test.

Afterward, you should plan to rest for several hours, even if you feel fine. This is to prevent fluid from leaking around the site of the puncture. You will do not need lie flat on your back the entire time.

How the Test will Feel

It may be uncomfortable to stay in position for the test. Staying still is important because movement may lead to injury of the spinal cord.

You may be told to straighten your position slightly after the needle is in place. This is to help measure the CFS pressure.

The anesthetic will sting or burn when first injected. There will be a hard pressure sensation when the needle is inserted. Often, there is some brief pain when the needle goes through the tissue surrounding the spinal cord. This pain should stop in a few seconds.

In most cases, the procedure takes about 30 minutes. The actual pressure measurements and CSF collection only take a few minutes.

Why the Test is Performed

This test is done to measure pressures within the cerebrospinal fluid and to collect a sample of the fluid for further testing.

CSF analysis can be used to diagnose certain neurologic disorders. These may include infections (such as meningitis) and brain or spinal cord damage. A spinal tap may also be  done to establish the diagnosis of normal pressure hydrocephalus.

Normal Results

Normal values typically range as follows:

Note: mg/mL = milligrams per milliliter; mEq/L = milliequivalents per liter

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

If the CSF looks cloudy, it could mean there is an infection or a buildup of white blood cells or protein.

If the CSF looks bloody or red, it may be a sign of bleeding or spinal cord obstruction. If it is brown, orange, or yellow, it may be a sign of increased CSF protein or previous bleeding (more than 3 days ago). There may be blood in the sample that came from the spinal tap itself. This makes it harder to interpret the test results.

CSF PRESSURE

CSF PROTEIN

CSF GLUCOSE

BLOOD CELLS IN CSF

OTHER CSF RESULTS

Additional conditions under which the test may be performed:

Risks

Risks of lumbar puncture include:

There is an increased risk of bleeding in people who take blood thinners.

Brain herniation may occur if this test is done on a person with a mass in the brain (such as a tumor or abscess). This can result in brain damage or death. This test is not done if an exam or test reveals signs of a brain mass.

Damage to the nerves in the spinal cord may occur, particularly if the person moves during the test.

Cisternal puncture or ventricular puncture carries additional risks of brain or spinal cord damage and bleeding within the brain.

Considerations

This test is more dangerous for people with:


Review Date: 5/28/2013
Reviewed By: Luc Jasmin, MD, PhD, FRCS (C), FACS, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles CA; Department of Surgery at Los Robles Hospital, Thousand Oaks CA; Department of Surgery at Ashland Community Hospital, Ashland OR; Department of Surgery at Cheyenne Regional Medical Center, Cheyenne WY; Department of Anatomy at UCSF, San Francisco CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.

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