Lumbar Puncture (or Spinal Tap)

What is it?

A lumbar puncture, also known as a spinal tap, checks for viruses, bacteria and fungi in the fluid in the space surrounding the spinal cord. This fluid is called the cerebrospinal fluid (CSF). A needle into the spine is inserted and the CSF is collected.

What is it for?

This test is done to check for infections to the brain or nervous system. The test can also help determine the source of the infection. It also can detect pressures within the cerebrospinal fluid and brain and spinal cord problems causing neurological disorders.

How to prepare

Communicate with your health care provider about:

  • Any bleeding disorders or problems you have
  • Medications you are taking especially blood thinners
  • Your immune system history
  • Any back surgeries you’ve had previously
  • Allergies


  • Backache
  • Headache
  • Bleeding
  • Infection

What happens during?

  • The procedure takes about 10 to 15 minutes
  • The health care provider will position you to make your back arch, opening the space between the bones of the spine
  • Your back will be cleaned and sterilized
  • Numbing medication will be used
  • The needle is inserted over the spine in your lower back. It takes about two to three minutes to collect the spinal fluid.
  • The needle is removed and the incision site is bandaged

What happens after?

  • You will stay in the hospital for several hours if your procedure is done on an outpatient basis
  • You will be asked to lie flat on your back or stomach to reduce the chance of a headache
  • Results of the spinal tap may take a few hours
  • Plan to have another person drive you home
  • You will be asked to limit your activities for 24 hours
  • The puncture site might be sore for one to two days

Side effects

Contact your health care provider immediately if you are at home and have:

  • Fever
  • Headache
  • Weakness or loss of sensation in your legs
  • Incontinence
  • Pain that does not get better