A cerebrospinal fluid (CSF) culture is a laboratory test to look for bacteria, fungi, and viruses in the clear fluid that moves in the space surrounding the spinal cord.

A sample of CSF is needed. This is usually done with a lumbar puncture. For information on how this procedure is performed, see spinal tap.

The sample is sent to the laboratory, where it is placed in a special dish (called a culture medium). The laboratory personnel watch to see if bacteria, fungi, or viruses grow in the dish. Growth means there is an infection.

For information on how to prepare for the procedure to obtain the CSF sample, see spinal tap.

For information on how it will feel to have a sample of CSF fluid removed, see spinal tap.

Your doctor may order this test if you have signs of an infection that affects your brain or nervous system. The test will help identify the origin of the infection. This helps your doctor determine the best course of treatment.

A normal result means no bacteria, viruses, or fungi grew in the laboratory dish. This is called a negative result.

An abnormal result means a fungus, virus, or bacterium grew in the laboratory dish. This is considered a positive culture and is a sign of an infectious meningitis. This does not necessarily mean the infection is contagious, unless it is meningococcal meningitis.

See also:

• Aseptic meningitis
• Brucellosis
• Cryptococcosis
• Myelomeningocele (children)

A laboratory culture poses no risk to the patient. For risks associated with the procedure done to get a CSF sample, see spinal tap.