The Basics
A spinal tap collects cerebrospinal fluid (CSF), which is the fluid that surrounds and cushions the brain and spinal cord. A spinal tap is often used to diagnose infections such as meningitis or diseases that affect the nervous system such as multiple sclerosis. It is also useful in diagnosing conditions such as cancer, brain or spinal cord injuries, and brain hemorrhages.
Samples of CSF are taken from the lower spine using a needle and are sent to a laboratory for analysis.
The test is usually done in a clinic or hospital by a trained health care professional.
Picture of the spine.
Risks and precautions
Certain risks are associated with a spinal tap and can include:
- excessive bleeding into the spine, especially in people who are on medications that impair blood clotting, such as acetylsalicylic acid (aspirin) or warfarin
- severe allergic reaction to the anesthesia used for the test (difficulty breathing, hives, swelling of the face and throat)
- infection (redness, pus, swelling)
- spinal cord nerve damage
Get immediate medical assistance if you experience any of these complications or side effects.
You can lower your risk of damage to the spinal cord by remaining still while the test is being performed. People with brain tumors or masses should not have a spinal tap done because this could cause brain damage or death.
Some people may experience complications or side effects other than those listed. Check with your doctor if you notice any symptom that worries you after your test. It is important that you understand all the risks of complications and side effects of the test, and what you or your doctor can do to avoid them. Make sure that your doctor is aware of all your concerns.
Before the test
Your doctor may want you to do an imaging test (i.e., CT scan) before a spinal tap to ensure that there is no swelling in your brain, which may prevent you from having this test done. Eat a light breakfast the morning of the test and drink more fluids a few days leading up to the test date.
If you are taking any prescription or over-the-counter (non-prescription) medications, supplements, or herbal products, make sure you inform your doctor or pharmacist. Ask them whether it is necessary for you to stop taking any of these medications and products before the test. It is also important to tell them if you have allergies to certain medications or have certain medical conditions.
Plan to have someone drive you home after the test.