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Multiple Sclerosis

Today, there are many medication options to treat MS. If one medication doesn’t work or causes severe side effects, there’s likely another option that could be a better fit.

Could It Be MS? How Doctors Test and Diagnose Multiple Sclerosis

Learn about the tests and exams physicians use to rule out other conditions and diagnose multiple sclerosis, or MS.

Mandy Armitage, MD profile image

Reviewed by Mandy Armitage, MD

Updated on April 7, 2025

Many times when doctors diagnose multiple sclerosis, it comes as a surprise to the patient. “They’re thinking they have an infection or some other mild medical complaint,” says Michelle Fabian, MD, a Neurologist at The Mount Sinai Hospital in New York City.

MS is a nervous system disease that affects your brain and spinal cord. The body’s immune system damages the myelin sheath.This is the material that surrounds and protects nerve cells. This damage slows down or blocks messages between your brain and your body, which can causing a wide range of debilitating symptoms. Symptoms of MS include weakness, blurry vision, and trouble balancing.

What are doctors looking for when they diagnose multiple sclerosis?

To diagnose multiple sclerosis, doctors first perform exams and tests to rule out other causes of the patient’s symptoms. Then, they use several strategies to determine if their symptoms fit the criteria for MS.

If a primary care doctor suspects MS, they’ll refer them to a neurologist. The neurologist will listen to the patient’s story, and then begin to seek out the source of their symptoms.

“What they’re looking for in the exam, is whether we can relate the symptom to a problem in the central nervous system, the brain or the spinal cord, or the peripheral nervous system, which are the nerves that connect the brain to the spinal cord,” says Dr. Fabian.

What tools and tests do doctors use?

The neurologist will perform a neurological exam, carefully examine the patient’s medical history, and conduct various tests to diagnose multiple sclerosis. These tests may include:

  • blood tests to rule out other possible conditions

  • magnetic resonance imaging (MRI) to look for MS lesions

  • evoked potentials (EP) to measure electrical activity in the brain

  • a spinal fluid analysis to look for a marker in their spinal fluid

Why is early diagnosis important?

If you’re feeling any symptoms that are unusual to you, like numbness, difficulty walking, dizziness, or cognitive changes, always check with your doctor. “We do want to get a patient on treatment sooner rather than later,” says Dr. Fabian. Many studies show that the earlier the treatment for MS, the better that patient will do in the long run.

References

National Multiple Sclerosis Society. (n.d.). How MS is diagnosed.

U.S. National Library of Medicine, MedlinePlus. (2021). Multiple sclerosis.

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