A spinal tap (also called lumbar puncture) removes fluid from the spine. This fluid is called cerebrospinal fluid. This test is done to rule out other possible illnesses that could be causing Alzheimer’s disease symptoms. This procedure takes about 20 minutes. The patient lies down on their side with their knees up near their chest. The lower part of the spine, where a needle will go in to withdraw the cerebrospinal fluid, is numbed with a local anesthetic. After the needle is taken out, the site where the needle was is covered up. A common side effect of this test is a mild headache.
Additional resources that provide more information on how spinal tap (lumbar puncture) is used to diagnose Alzheimer’s disease: