How Is a Multiple Sclerosis Diagnosis Made?

Written by George Krucik, MD, MBA | Published on November 4, 2013
Medically Reviewed by Treacy Colbert on November 4, 2013

The sooner a multiple sclerosis diagnosis is made, the sooner treatment can begin.

A Careful Process

If you’re concerned that you or someone you care for has multiple sclerosis (MS), it’s important to seek a doctor’s advice right away. Even early-stage MS can result in lasting neurological damage. Confirming or ruling out MS without delay means that treatment can be started as soon as possible if needed.

Unfortunately, no test, set of symptoms, or physical changes alone are enough to definitively diagnose MS. Read more to learn about what to expect from the diagnostic process.  

Start With Medical History

A thorough review of your medical history is the first step in diagnosing MS. Your doctor will ask when your symptoms began and if you have noticed any patterns or triggers. You’ll list tests or treatment you’ve had, medications, allergies, family health, and any accidents or surgeries.

Your doctor will also ask you about your diet, bladder and bowel habits, and sexual health. They may evaluate potential environmental factors, such as exposure to toxins or travel to high-risk areas.  

Neurological Exam

The neurological exam assesses nervous system functioning. You’ll answer questions about the date, time, and place. The doctor will ask you to push, pull, and stand so they can evaluate your motor function and balance. They’ll also test your ability to feel temperature and sensation.

This exam includes a reflex test, and an evaluation of the 12 cranial nerves of the brain. These nerves measure your ability to see, chew, swallow, and smell, among other things. Your doctor may give a tentative diagnosis of MS based on your medical history and neurologic exam.

Magnetic Resonance Imaging

MS can’t be diagnosed based on magnetic resonance imaging (MRI) alone. However, it’s an important tool in the diagnostic process. It can detect lesions (scarring) on the brain or spinal cord.

MRI can also distinguish between old and recently formed lesions. However, the MRIs of approximately 5 percent of people who have MS don’t show brain lesions, according to the National Multiple Sclerosis Society. Lesions on the brain can signify a condition other than MS in elderly people.

Visual Evoked Potentials

During a visual evoked potentials (VEP) test, you’ll sit in front of a screen that shows alternating patterns. This test measures the transmission of visual stimulation along the path of the optic nerve.

Damage to the myelin sheath on the optic nerve slows transmission of these signals in people with MS. This test can detect potential MS-related changes even before you experience them.  

Spinal Tap

A spinal tap (lumbar puncture) is an examination of cerebrospinal fluid. The National Multiple Sclerosis Society states that fluid shows oligoclonal bands in 90 to 95 percent of people with MS. This indicates a central nervous system (CNS) immune response.

Oligoclonal bands are proteins called immunoglobulins that suggest CNS inflammation. The presence of these bands alone doesn’t indicate MS, because this immune response can occur with other conditions.

Blood Tests to Rule Out Other Conditions

No blood test detects MS. A blood test can confirm or rule out other conditions such as Lyme disease, AIDS, lupus, and certain genetic disorders whose symptoms overlap with symptoms of MS.

In addition, certain blood tests can help determine if myelin sheath damage is due to a non-MS disease. Some possibilities include neuromyelitis optica (NO) or acute disseminated encephalomyelitis (ADEM).

Diagnostic Criteria

A diagnosis of MS must meet these criteria:

  • evidence of damage to two separate areas of the nervous system (brain, spinal cord, optic nerve)
  • evidence that the CNS damage occurred at least one month apart
  • no evidence that the damage was caused by other diseases

Diagnosing MS in Children and Teens

Symptoms begin before age 18 in approximately 2 to 5 percent of people with MS. In children, MS symptoms may masquerade as other childhood diseases, which make diagnosis more complicated.

In addition, young children may not be able to verbalize certain visual symptoms, particularly if they haven’t yet started to read.

Considerations for Older Adults

Late-onset MS is defined as initial symptom presentation after age 50. It occurs in an estimated 4 to 9.6 percent of cases, according to an analysis of different studies published in the journal Neurological Sciences.

Sorting out the symptoms and their causes may take longer in cases of late-onset MS. Some symptoms in older adults that can overlap with age-related conditions include:

  • loss of muscle strength
  • balance problems
  • weakness
  • cognitive deficits
  • fatigue
  • vision changes

Patience, Persistence, Expertise

Arriving at a diagnosis of MS takes time and persistence. It’s important to seek care from a doctor who has experience in diagnosing and treating MS.

A prompt and accurate diagnosis allows early treatment with disease-modifying medications. This can cut down MS attacks, lower the number of new lesions, slow the progress of the disease, and improve quality of life.

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