How Multiple Sclerosis Is Diagnosed

It can be a challenge for doctors to diagnose multiple sclerosis (MS). There’s no one test that can definitely show if someone has it. And there are many conditions with symptoms that can seem like MS.

But a neurologist who specializes in treating the disease should be able to look into how you’re feeling and help you figure out if your symptoms mean you have MS or another problem.

Getting a Diagnosis

Your doctor will start by asking you about your medical history and your symptoms. She’ll also do a few tests to see if your brain and spinal cord are working as they should. These include:

  • Imaging tests, like an MRI, to take a closer look at your brain
  • Spinal taps, also called lumbar punctures, to check the fluid that runs through your spinal column
  • Electrical tests, called evoked potentials, to see if MS has affected your nerve pathways
  • Blood tests

What Does an MRI Show?

It's the best way for doctors to see any brain changes caused by multiple sclerosis. It can show your neurologist clear signs of inflammation in the deep parts of your brain or spinal cord that are red flags for the condition.

But older people or those with high blood pressure and diabetes also can have the same kinds of spots on a brain MRI. So your doctor will consider other info, including your symptoms, along with the scan results before she makes a diagnosis.

Also, an MRI result that says things are normal does not absolutely rule out MS. About 5% of people with multiple sclerosis don’t have lesions in the brain that show up on the test. They may have them in places that the scan can’t show.

Will I Need a Spinal Tap?

When doctors do this test, they’re looking closely at the fluid in your spine, called cerebrospinal fluid, for higher levels of proteins and other substances that are signs of the disease. These can be helpful in diagnosing MS, but they’re not absolute proof of the condition. Your doctor can tell you if you need to have a spinal tap.


Other Tests

Electrical tests of your nerves, called evoked potentials, can help doctors confirm if the condition has affected the parts of your brain that help you see, hear, and feel. Your doctor will place wires on your scalp to test your brain's response as you watch a pattern on a video screen, hear a series of clicks, or get electrical pulses on your arm or leg.

Your doctor may check your blood to help rule out conditions that can look like MS. It’s not possible, though, to diagnose the disease with a blood test.

After a Diagnosis

Getting an MS diagnosis can be a lengthy process. When some people finally learn they have the condition after months or years of symptoms, they take the news as something of a relief. For others, it can be shocking. Either way, you’ll probably have concerns about what the disease means for your life and your family. That's completely understandable.

Talk with others -- your friends, your doctor, a support group, or a counselor -- about how you’re feeling. Your health care team can help you decide on the best ways to treat your disease and live with it day to day. MS affects everyone differently, so what one person with the condition feels may not be what will happen to you.

WebMD Medical Reference Reviewed by Neil Lava, MD on September 11, 2016


National Multiple Sclerosis Society.

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