Diagnosing multiple sclerosis (MS) takes several steps. One of the first steps is a general medical evaluation that may include:
- a physical exam
- a discussion of any symptoms
- your medical history
If your doctor suspects that you have MS, you may need to take more tests. This includes a lumbar puncture test, also known as a spinal tap.
MS shares symptoms with other health problems, so your doctor will need to determine whether it’s MS that’s causing your symptoms and not another condition.
Other tests your doctor might perform to rule out or confirm a diagnosis of MS include:
- blood tests
- MRI, or magnetic resonance imaging
- evoked potential test
A lumbar puncture, or spinal tap, involves testing your spinal fluid for signs of MS. To do so, your doctor will insert a needle into the lower part of your back to remove spinal fluid.
According to the Cleveland Clinic, a lumbar puncture is the only way to directly and accurately determine how much inflammation you have in your central nervous system. It also shows the activity of your immune system in these parts of your body, which is important for diagnosing MS.
During a lumbar puncture, spinal fluid generally is drawn from between your third and fourth lumbar in your lower spine using a spinal needle. Your doctor will ensure that the needle is positioned between your spinal cord and the cord’s covering, or the meninges, when drawing fluid.
A spinal tap can tell you if the amount of protein, white blood cells, or myelin in your spinal fluid is too high. It can also reveal if the fluid in your spine contains an abnormal level of antibodies.
Analyzing your spinal fluid also can show your doctor whether you might have another condition and not MS. Some viruses can cause signs and symptoms similar to MS.
A lumbar puncture should be given along with other tests to confirm a diagnosis. The procedure can reveal issues with your autoimmune system, but other conditions that affect your nervous system, like lymphoma and Lyme disease, can also show high levels of antibodies and proteins in your spinal fluid, hence the need to confirm a diagnosis with additional tests.
MS is often difficult for doctors to diagnose because a spinal tap alone can’t prove whether you have MS. In fact, there is no single test that can confirm or deny a diagnosis.
Other tests include an MRI to detect lesions on your brain or spinal cord, and an evoked potential test to help detect nerve damage.
A lumbar puncture is a common test used to diagnose MS, and it’s a relatively simple test to perform. It’s generally the first step in determining if you have MS if you’re showing symptoms. Your doctor will determine whether further tests are needed to confirm a diagnosis.