During the test
You will be asked to undress and change into a gown. You will lie on your side with your knees bent towards your chest and chin down. A health care professional will clean your back with an antiseptic and inject an anesthetic into your lower spine to numb the area. You may feel stinging in your back when the anesthetic is given.
A special needle is inserted into your lower back to collect a CSF sample and to measure the fluid pressure in the spine. It is very important that you remain still to prevent the needle from potentially injuring the spinal cord. You might feel some pressure in your back and temporary pain when the needle is in your back.
Once the test is done, the needle will be removed, the area will be cleaned, and a bandage will be placed over the injection site. The sample will be sent to the laboratory to be analyzed. You may be asked to remain on your side after the test is done.
The process generally takes about 30 to 45 minutes.
After the test
You will rest for several hours after the test to make sure extra CSF does not leak out from the puncture site. You may feel these side effects after this test:
- headache
- discomfort or pain in the lower back
The laboratory will generate a report and send it to your doctor, who will use the information to make a diagnosis. Ask your doctor when you can expect your test results to be made available.