Cerebrospinal fluid (CSF) analysis is a laboratory test to examine a sample of the fluid surrounding the brain and spinal cord. This fluid is a clear, watery liquid that protects the central nervous system from injury and cushions it from the surrounding bone structure. It contains a variety of substances, particularly glucose (sugar), protein, and white blood cells from the immune system. The fluid is withdrawn through a needle in a procedure called a lumbar puncture.

The purpose of a CSF analysis is to diagnose medical disorders that affect the central nervous system. Some of these conditions include: meningitis, encephalitis, tumors or cancers of the nervous system, syphilis, bleeding (hemorrhaging) around the brain and spinal cord, multiple sclerosis, and Guillain-Barré syndrome.

In some circumstances, a lumbar puncture to withdraw a small amount of CSF for analysis may lead to serious complications...