Lumbar puncture for acute lymphoblastic leukaemia (ALL)

You have fluid taken during a lumbar puncture to check whether leukaemia cells have spread into the fluid around the brain and spinal cord. The fluid is called cerebrospinal fluid (CSF).

Doctors or nurses remove some of the fluid to test for cancer cells. They use a needle to take a sample of the CSF from your lower back.

Diagram showing how you have a lumbar puncture

You normally have this test under local anaesthetic. This means you are awake but the area is numb. It usually doesn't take very long and is generally not very painful.

This video explains how you have a lumbar puncture and the side effects you might have. 

Preparing for your lumbar puncture

Check your appointment letter for how to prepare for your lumbar puncture test. You are usually able to eat and drink before your test. Tell your doctor if you’re taking medicines that changes how your blood clots. This includes:

  • warfarin or heparin
  • aspirin
  • clopidogrel
  • apixaban or rivaroxaban
  • ticagrelor

Your doctor will tell you if you need to stop taking these medicines and how long before your test. All other medicines you can usually take as normal. 

Children and some adults may have this under a general anaesthetic (GA) Open a glossary item or with sedation Open a glossary item. If you are having it this way you have to stop eating and drinking for some time before the test. Your appointment letter or a member of the healthcare team will tell you how long for.

Just before the procedure, you are asked to go to the toilet to empty your bladder and bowels.

What happens during a lumbar puncture?

Your doctor will give you information about the procedure and ask you to sign a consent form. This is a good time to ask any questions you may have.

A staff member asks you to take off your upper clothing and put on a hospital gown.

You usually lie on your side with your knees tucked up into your chest. It's important to stay as still as you can during the test, so make sure you are comfortable before it starts.

The doctor or nurse drapes some sterile covers over you. Then they clean the area with antiseptic fluid, which can feel cold.

You have an injection of anaesthetic into the area, this can sting for a few seconds. When the area is numb, the doctor or nurse puts the lumbar puncture needle in through the skin. It goes into the small of your back and into the space around the spinal cord. You might feel some pressure when the needle goes in.

Once it's in the right place, the fluid drips out into a pot. This only takes a few seconds.

Your doctor or nurse takes the needle out and puts a dressing or plaster on your back.

The whole test takes about 20 to 30 minutes. It can be uncomfortable but it's not usually painful.

After your lumbar puncture

You lie flat for an hour or so after the test.

Tell your doctor or nurse if you have a headache, so they can give you some painkillers. Lying flat and drinking plenty of fluids may relieve your headache. This may last for a couple of days so make sure you have painkillers at home. 

You will have a dressing on the skin where they did the test. You usually remove this the next day.

You can usually go home the same day. 

Getting your results

The fluid is sent to the laboratory and looked at under a microscope for cancer cells.

It can take time for test results to come through. How long will depend on why you're having the test. It could be a day or two but can be up to a couple of weeks.

If you have not had your results a few weeks after your test, you could contact your doctor to chase your results for you.

Waiting for results can be an anxious time. It might be helpful to talk to someone close to you. 

You can also contact the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9 to 5, from Monday to Friday.

Possible risks

A lumbar puncture is a very safe procedure but your nurse will tell you who to contact if you have any problems after your test.

Your doctors will make sure the benefits of having a lumbar puncture outweigh these possible risks.


If your headache doesn't get better contact your hospital team.


You might have lower back pain for a couple of days after the test. Contact your hospital team if the pain is severe.


You might notice a small amount of blood stained ooze on the plaster or dressing. 

Very rarely you may have bleeding for more than 15 minutes. Contact your hospital team, they can give you advice on what best to do.


This is very rare. Contact the hospital straight away if you:

  • have a high temperature
  • are being sick
  • are sensitive to bright light
  • have tingling or numbness in your legs
  • have a severe headache
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    Annals of Oncology, 2016. Volume 27, Issue 5, Pages v69 to v82

  • Hoffbrand’s Essential Haematology (8th Edition)
    AV Hoffbrand and D A Steensma
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  • Body position and intake of fluids for preventing headache after a lumbar puncture 
    I Arevalo-Rodriguez and others
    Cochrane Database of Systematic Reviews 2016, Issue 3.

  • Oxford handbook of clinical medicine (9th edition)
    M Longmore, IB Wilkinson, A Baldwin and E Wallin
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  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.

Last reviewed: 
28 May 2021
Next review due: 
28 May 2024

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