Lumbar puncture

This test collects cerebrospinal fluid (CSF), which floats around the brain and spinal cord. The fluid can be tested to see if there are any cancer cells or infection in the fluid.

You will be asked to lie down on a couch on your side with your knees curled up under your chest or in a sitting position. The doctor doing the procedure will tell you which position they want you to be in. It is important to stay as still as possible during the test.

The doctor will inject local anaesthetic into the lower part of your back. A thin needle will then be put into the space around your spinal cord - you may feel some pressure when the needle goes in. Once the needle is in place, a small amount of spinal fluid is withdrawn. For some cancers, chemotherapy can be given into the spinal fluid after the sample has been removed.

Does it hurt?

You will need to remain still during the test, and may feel some discomfort as the needle goes in. There might also be some pain, although the anaesthetic usually helps.

How long does it take?

About 30 minutes

After the test

You will not be allowed to sit up or get out of bed for 1–2 hours afterwards. This is to prevent headaches. You will also be advised to drink plenty of fluids to reduce the risk of headaches. If your headache doesn't get better, contact your nurse or the hospital.