Lumbar puncture

A lumbar puncture is a test to check the fluid that circulates around the brain and spinal cord. This is called the cerebrospinal fluid or CSF.

Why do I need a lumbar puncture?

A lumbar puncture can check for cancer cells or for infection in the CSF.

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

You normally have this test in the outpatient department under local anaesthetic. This means you are awake but the area is numb. 

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. They 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. But do check with your doctor or nurse beforehand.

Children and some adults may have this under a general anaesthetic  or with sedation . 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 test, 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 you put on a hospital gown.

You usually lie on your side with your knees tucked up into your chest. Some people might have this while sitting. You bend forwards while sitting with your back to the doctor. You might lean on a couch or a table with your head supported by pillows.

It's important to stay as still as you can during the test, so the person doing the test makes 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

After the test, you usually stay in the hospital for a while, and you need to lie flat. The time can vary, in some hospitals, you may have to lie flat for around 4 hours. During this time, your nurse checks your pulse and blood pressure. They will also check the area where the needle was put in. This is called the puncture site. 

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 it's important to 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. You should have someone to take you home, and you should not drive for at least 24 hours. Your healthcare team will tell you what you can do when you get home. This includes whether you need to continue to lie flat and for how long.

Possible risks

A lumbar puncture is a 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.

Some of the risks include:

Headache

Headaches can develop up to two days after the test and can continue for a couple of days afterwards. Your headache may get worse when you stand up. It can help to lie down flat and drink plenty of fluids. Your nurse will tell you what painkillers to take. If you have severe headaches or they're getting worse, contact your hospital 24 hour advice line.

Lower back pain

You might have lower back pain after the local anaesthetic has worn off. This usually lasts for a couple of days after the test. Contact your hospital team if the pain is severe.

Bleeding

You usually have a small spot of blood on the dressing on your back. Contact your hospital team if the bleeding continues.

Infection

Contact your hospital advice line if you have symptoms of an infection. This includes:

• a temperature over 37.5°C or below 36°C
• feeling cold or shivery
• aching muscles
• feeling generally unwell
• the puncture site looking red or feeling sore

You should also contact your hospital advice line if you:

• are being sick (vomiting)

• are sensitive to bright lights

• have tingling or numbness in your legs

• have a severe headache

• have difficulty having a pee (passing urine)

• have fluid leaking from the puncture site

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 test results can be a worrying time. You might have contact details for a specialist nurse. You can get in touch with them for information and support if you need to. It may also help to talk to a close friend or relative about how you feel. 

More information

We have more information on tests, treatment and support if you have been diagnosed with cancer.