Facts on Spinal Fluid Sampling or Lumbar Puncture

The Facts on Spinal Fluid SamplingCerebrospinal fluid (CSF) is a watery, serum-like fluid that circulates through the ventricles of the brain and in the cavity of the spinal cord. It acts somewhat like a shock absorber for protection of these areas.

Scroll down for more information on the procedure. For a firsthand account of what a lumbar puncture is like, click here.

Why CSF Is Important in Neurodegenerative Research?

Examining cerebrospinal fluid is a key part of research into healthy brain aging and brain disorders, including dementing illnesses. CSF contains tau, other proteins, and important chemical particles known as biomarkers. These markers may indicate the existence of a disease process in an individual.

Because CSF directly "bathes" the brain, it is considered the best course in which to study those biomarkers related to brain health and disease. While some types of biomarkers may also be present in blood and urine, these fluids undergo processing in the liver and kidneys; thus the type and concentration of biomarkers in blood and urine are not the same as in CSF, which is considered the 'gold standard' of source material.

How Is CSF Obtained?

CSF is obtained through a simple and safe process known as a lumbar puncture (LP). The sample is quick and involves only the slightest discomfort. There is no risk of paralysis. The very small needle that is used to draw the CSF is never in contact with the spinal cord.

The person giving the CSF sample can lie comfortably on his or her side on an exam table or sit during the procedure. The skin is swabbed with a cleansing solution. A local anesthetic is injected under the skin where the needle will be placed, making the area totally numb. A small needle is inserted into the lower back, below where the spinal cord itself ends in the spinal cavity, in between the bones of the spine to reach the fluid. The needle is not inserted into the bones of the spine. Only about 3 tablespoons of fluid are drawn out from the spinal cavity.

Are There Risks Involved?

There may be slight discomfort or bruising of the skin where the needle was inserted, similar to what may occur when one gives blood. In less than 10% of cases individuals report a headache which usually responds to treatment with over-the-counter pain relievers. In very rare instances, more severe headachee may occur. All precautions are taken to anticipate potential problems and minimize any risks.

After resting for about 30 minutes, the person giving the CSF sample can safely drive home and resume normal activity.

This material is excerpted from an article appearing in the Penn Alzheimer's Disease Center Quarterly.

What's It Really Like?

Read a firsthand account of a Penn Udall Center research participant's first LP by clicking here.