Tests and Procedures
Lumbar puncture (spinal tap)
Why it's done
A lumbar puncture may be done to:
- Collect cerebrospinal fluid for laboratory analysis
- Measure the pressure of your cerebrospinal fluid
- Inject spinal anesthetics, chemotherapy drugs or other medications
- Inject dye (myelography) or radioactive substances (cisternography) into cerebrospinal fluid to make diagnostic images of the fluid's flow
Information gathered from a lumbar puncture can help diagnose:
- Serious bacterial, fungal and viral infections, including meningitis, encephalitis and syphilis
- Bleeding around the brain (subarachnoid hemorrhage)
- Certain cancers involving the brain or spinal cord
- Certain inflammatory conditions of the nervous system, such as multiple sclerosis and Guillain-Barre syndrome