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Lumbar Puncture

  • Cynthia M. Johnson, MA
Publication Type:


Lumbar Puncture

(Cerebrospinal Fluid Analysis; Cerebrospinal Fluid Tap; Spinal Tap)


A lumbar puncture is a test of the cerebrospinal fluid (CSF) around the spine and brain. This fluid provides protection and nutrition to the brain and nerve cells. It also helps remove waste products from the brain.

Lumbar Puncture Method

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Reasons for Procedure

The test is done to look for anything that is not normal with a person's CSF. It may be done to help diagnose health problems, such as:

  • Brain infection
  • Neurological disorders, such as multiple sclerosis
  • Bleeding in the brain or spinal cord
  • A buildup of CSF in the brain

It may also be done to treat health problems. It can be used to:

  • Give medicine directly to the spine, such as chemotherapy, antibiotics, and anesthesia
  • Deliver contrast material for imaging studies
  • Drain CSF to lower pressure within the brain

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:

  • Excessive bleeding
  • Infection
  • Problems from anesthesia, such as wheezing or sore throat
  • Compression on the brain stem

What to Expect

Prior to Procedure

A lumbar puncture may be done on short notice, so there may be no steps to take before the procedure. In others, the surgical team may meet with you to talk about:

  • Anesthesia options
  • Any allergies you may have
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before surgery
  • Fasting before surgery, such as avoiding food or drink after midnight the night before
  • Arranging for a ride to and from surgery


Local anesthesia will be used. The area will be numbed.

Description of Procedure

You will likely lie on your side with your knees drawn up in front. Some punctures may be done while you sit on the edge of the bed. The site will be cleaned. A needle will be inserted through the lower back and into the spinal canal. A sample of CSF will be taken through the needle.

The doctor will note the pressure of the CSF. Medicines or contrast material may also be injected as part of treatment and diagnosis. The needle will be removed. A bandage will be placed over the site.

How Long Will It Take?

About 30 to 45 minutes.

Will It Hurt?

Anesthesia will prevent pain during the procedure. There may be back pain when it is complete. Medicine can help.

Post-procedure Care

At the Hospital

After the procedure, the staff may:

  • Give you pain medicine
  • Have you lie down and monitor you for 10 to 60 minutes

At Home

Rest and home care will be needed for at least 24 hours. Medicine will be given to help with any pain.

Call Your Doctor

Call the doctor if you are not getting better or you have:

  • A headache that lasts for more than 24 hours
  • Nausea or vomiting
  • Signs of infection, such as fever and chills
  • Redness, swelling, bleeding, or leaking from the puncture site
  • Numbness, tingling, or pain in your lower back or legs
  • Weakness in your lower legs or problems walking
  • Problems passing or controlling urine (pee) or stool (poop)
  • A stiff neck
  • Pain is not eased by medicine

If you think you have an emergency, call for medical help right away.





  • Lumbar puncture (LP). EBSCO DynaMed website. Available at
  • Lumbar puncture. Radiological Society of North America Patient website. Available at:
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.