A cerebrospinal fluid (CSF) smear is a microscopic examination of the clear fluid that moves in the space surrounding the spinal cord and brain. CSF protects the brain and spinal cord from injury.
Spinal fluid smear; Cerebrospinal fluid smear
How the test is performed:
A sample of CSF fluid 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 a laboratory, where a tiny amount is spread on a glass slide. A member of the laboratory team looks at the sample under a microscope. The smear shows the color of the fluid and the number and shape of cells present in the fluid. Other tests, such as a Gram stain, may be done to check for bacteria.
How to prepare for the test:
For information on how to prepare for the procedure to obtain the CSF sample, see spinal tap .
How the test will feel:
The laboratory test is painless and does not involve the patient.
For information on how it will feel to have a sample of CSF fluid removed, see spinal tap .
Why the test is performed:
The test is done to check for signs of infection in a sample of CSF.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean:
If bacteria are present, that indicates bacterial meningitis . Other kinds of infections might include tuberculosis and fungal infections. Certain bacteria or viruses can also be detected using special tests.
What the risks are:
A laboratory smear poses no risk to the patient. For risks associated with the procedure done to get a CSF sample, see spinal tap .