Spinal Tap (Lumbar Puncture)
What is a spinal tap (lumbar puncture)?
To perform a spinal tap (also called a lumbar puncture), your healthcare provider inserts a needle into your lower back to get a sample of cerebrospinal fluid. Cerebrospinal fluid is the clear liquid that surrounds your spine and brain. A lab tests the fluid sample to check:
- Presence of bacteria, fungi or abnormal cells.
- Glucose (blood sugar) levels.
- Protein types and levels.
- White blood cell types and levels.
Why do healthcare providers perform spinal taps (lumbar punctures)?
Your healthcare provider may perform a spinal tap to test for:
- Bleeding in the brain (intracranial hemorrhage).
- Leukemia or other cancers.
- Meningitis and encephalitis (brain and spinal cord infections).
- Multiple sclerosis or other autoimmune disorders.
- Myelitis (spinal cord inflammation).
- Excess cerebrospinal fluid.
Healthcare providers also use spinal taps to:
- Administer regional anesthesia, such as an epidural to block pain in the lower part of the body.
- Inject dye for an X-ray diagnostic test (myelogram).
- Inject cancer medications or muscle relaxers.
- Relieve intracranial (head) pressure.