Spinal tap; Ventricular puncture; Lumbar puncture; Cisternal puncture; Cerebrospinal fluid culture
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. It has the same consistency as water. The test is also used to measure pressure in the spinal fluid.
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.
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 not need to lie flat on your back the entire time.
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 CSF 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.
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 values typically range as follows:
Normal value ranges may vary slightly among different laboratories. Talk to your provider 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.
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.
BLOOD CELLS IN CSF
OTHER CSF RESULTS
Additional conditions under which the test may be performed:
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.
This test is more dangerous for people with:
Griggs RC, Jozefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 396.
Rosenberg GA. Brain edema and disorders of cerebrospinal fluid circulation. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 59.
Last reviewed on: 6/1/2015
Reviewed by: Daniel Kantor, MD, Kantor Neurology, Coconut Creek, FL and Immediate Past President of the Florida Society of Neurology (FSN). Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.