Lumbar Puncture Test

A lumbar puncture (spinal tap) test drains a small sample of cerebral spinal fluid from the lower spine. A needle is inserted between the vertebrae (backbones) in the lower back and into the space containing the spinal fluid.

What is it?

  • a procedure to remove a small sample of cerebral spinal fluid from the lower spine
  • this fluid surrounds and cushions the brain and spinal cord

How long does it take?

  • about 20 to 30 minutes
  • there is a possible 2-hour recovery period after the test, which will take place here at the Neurology Clinic

Why is the lumbar puncture test performed?

  • to determine the spinal fluid pressure
  • to obtain a specimen for testing (for either infection or bleeding)
  • to relieve pressure around the brain by removing fluid
  • to inject medications around the spinal cord

Does it hurt?

  • you may experience pressure when the needle is inserted. You may also feel some fleeing leg pain while the needle is positioned because it may briefly touch a floating nerve ending.

Where is it conducted?

  • the Neurology Clinic Treatment Room
  • 2nd floor Carver Pavilion

How many lumbar puncture tests are conducted each year?

  • several hundred

What should you do to prepare for the test?

  • eat normal meals
  • if you are an outpatient, please bring a relative or friend who can drive you home
  • continue taking prescribed medications unless your doctor gives other instructions

How is it performed?

  • you will lie on your side with your knees drawn up toward your chin as far as possible
  • the doctor will cleanse the skin over your spinal column with iodine
  • an injection of local anesthetic may be given at the puncture site
  • a needle is inserted into your spinal fluid space
  • a long, thin tube called a manometer is attached to the needle to measure the fluid's pressure
  • spinal fluid is collected into specimen tubes for laboratory testing

Frequently asked questions

Q: What if I'm unable to flex my back and legs?
A: The test can be done without bending or while sitting.

Q: Is the entire needle put into my back?
A: No, but the needle must be long enough to pass through the muscles of the lower back.

Q: Can I be paralyzed if the needle hits the spinal cord?
A: No, there is no need to worry about spinal cord damage. The needle is inserted well below the spinal cord.

After the test

  • you will be asked to lie on your stomach for about 30 minutes
  • after that, you will be asked to lie on your back or side for 15 to 90 minutes
  • your nursed will check the puncture site periodically for swelling or leakage of spinal fluid. They will also ask you to wiggle your toes and move your legs.
  • report any of the following symptoms to the doctor or nurse:
    • headache
    • tingling
    • numbness or pain in your lower back and legs
    • problems with urination
  • you may return to your hospital room or home, unless given other instructions from the doctor
  • if you are being driven home, you should lie down in the vehicle, if possible
  • you will learn the test results either from the doctor before you leave, or from a copy of the letter sent to your personal physician

Instructions to follow at home

  • drink 8 to 12 glasses of fluid (no alcohol) in the next 12 hours, unless your doctor indicates otherwise
  • remain quiet for the next 24 hours
  • avoid any strenuous physical activity for 48 hours
  • if you develope a headache, lie flat for the next 12 to 24 hours or until the headache goes away. Remember to drink plenty of fluids.
  • if your headache persists, call your home physician or the physician at the hospital who performed the lumbar puncture test.

Neurology clinic hours

  • during regular hours: call the nurses' station at (319) 356-2957 
  • after hours and on weekends: neurology resident on-call at (319) 356-1616

University of Iowa Department of Neurology