Key takeaways

  • Diagnosing MS typically involves multiple tests to rule out other conditions, as there is no single definitive test for MS.
  • Magnetic resonance imaging (MRI) is the primary diagnostic tool for MS. It helps doctors identify abnormalities, demyelination, and inflammation in the central nervous system.
  • In addition to blood tests and MRIs, lumbar punctures and evoked potential tests can help support MS diagnosis by analyzing cerebrospinal fluid and measuring electrical activity in the brain.

Multiple sclerosis (MS) is a chronic, progressive autoimmune condition that affects the central nervous system. MS occurs when the immune system attacks the myelin that protects the nerve fibers in the spinal cord and brain.

Early symptoms of MS can vary from person to person, but typically include:

  • vision issues known as optic neuritis
  • fatigue
  • numbness and tingling
  • weakness and impaired balance

If you or someone you love is experiencing symptoms similar to these, schedule a doctor’s appointment. If the doctor suspects MS, they’ll likely order several different tests to confirm a diagnosis.

This article reviews the type of tests a doctor may order and what these tests can tell you.

Blood tests will likely be part of the initial testing if your doctor suspects you might have MS. Blood tests can’t currently result in a firm diagnosis of MS, but they can rule out other conditions. These other conditions include:

Blood tests are especially valuable in the diagnosis of these conditions. Blood tests can also reveal abnormal results, which can help in the diagnosis of disorders such as cancer or a vitamin B12 deficiency.

Magnetic resonance imaging (MRI) is the test of choice for diagnosing MS in combination with a neurological physical examination.

MRIs use radio waves and magnetic fields to evaluate the relative water content in tissues of the body. They can detect normal and abnormal tissues and can spot irregularities.

MRIs offer detailed and sensitive images of the brain and spinal cord.

Goal of a diagnostic MRI for MS

Doctors will be looking for three things when they order MRI testing for possible MS:

  • any abnormalities that could rule out MS
  • evidence of demyelination
  • inflammation in the central nervous system

The layer of myelin that protects the nerve fibers is fatty and repels water when it’s undamaged. If the myelin has been damaged, however, this fat content is reduced or stripped away entirely and no longer repels water. The area will hold more water as a result, which can be detected by MRIs.

In MS, active lesions often show inflammatory demyelination, while old lesions may show scarring that is often described as “sclerosis.”

To diagnose MS, doctors must find evidence of demyelination. In addition to ruling out other potential conditions, an MRI can provide solid evidence that demyelination has occurred.

How to prepare for a diagnostic MRI

Before you go in for your MRI, you should remove all jewelry. If you have any metal on your clothes (including zippers or bra hooks), you’ll be asked to change into a hospital gown.

You’ll lie still inside the MRI machine (which is open on both ends) for the duration of the procedure, which takes between 45 minutes and 1 hour. Let your doctor and technician know ahead of time if you have:

  • metallic implants
  • a pacemaker
  • tattoos
  • implanted drug infusions
  • artificial heart valves
  • a history of diabetes
  • any other conditions that you think could be relevant

A lumbar puncture, also called a spinal tap, is sometimes used in the process of diagnosing MS. This procedure will remove a sample of your cerebrospinal fluid (CSF) for testing.

During the procedure, a needle is inserted into your lower back, between vertebrae, and into the spinal canal. This hollow needle will collect the sample of CSF for testing.

A lumbar puncture typically takes about 30 minutes, and you’ll be given a local anesthetic. You’ll probably be asked to lie on one side with your spine curved.

After the area has been cleaned and a local anesthetic has been administered, a doctor will insert the hollow needle into the spinal canal to withdraw one to two tablespoons of CSF.

You may be asked to stop taking any blood thinners before the test to prevent excessive bleeding. After the test, you will need to lie down for about an hour and make sure to drink an ample amount of fluids to avoid a headache.

Goal of a diagnostic lumbar puncture for MS

Doctors who order lumbar punctures during the process of an MS diagnosis will use the test to rule out conditions with similar symptoms. They’ll also look for signs of MS, such as:

  • elevated levels of antibodies called IgG antibodies
  • proteins called oligoclonal bands
  • an unusually high number of white blood cells

People with MS may have a white blood cell count that’s up to seven times higher than normal. However, these abnormal immune responses can also be caused by other conditions.

It’s also estimated that 5% to 10% of people with MS don’t show any abnormalities in their CSF.

Evoked potential (EP) tests measure the electrical activity in the brain that occurs in response to stimulation, such as sound, touch, or sight. Each type of stimulus evokes minute electrical signals, which can be measured by the electrodes placed on the scalp to monitor activity in certain areas of the brain.

There are three types of EP tests. The visual evoked response (VER or VEP) is the one most commonly used to diagnose MS.

When doctors order an EP test, they’re going to look for impaired transmission along the optic nerve pathways. This typically happens early in most MS patients. However, before concluding that abnormal VERs are due to MS, other ocular or retinal disorders must be excluded.

No preparation is necessary to take an EP test. During the test, you’ll sit in front of a screen that has an alternating checkerboard pattern on it. You may be asked to cover one eye at a time. It does require active concentration, but it’s safe and noninvasive.

If you wear glasses, ask your doctor ahead of time whether you should bring them.

Medical knowledge is always advancing. As technology and our knowledge of MS advance, doctors may find new tests to simplify the MS diagnosis process.

A blood test is being developed to detect biomarkers associated with MS. While this test likely won’t be able to diagnose MS on its own, it can help doctors evaluate risk factors and make diagnosis just a little easier.

What are the most common symptoms of MS?

There are many potential symptoms of MS, and people with the condition are affected differently. That said, some of the most common symptoms include:

  • issues with your eyes or your vision, such as blurry vision or eye pain
  • persistent mild or moderate fatigue
  • numbness or tingling in different parts of your body
  • feeling dizzy or off balance
  • muscle weakness
  • feeling the urge to pee more often or being unable to control
  • problems with memory or concentration

What conditions are most commonly mistaken for MS?

Conditions that are most commonly mistaken for MS include:

What’s the average age of diagnosis for MS?

Most people who receive an MS diagnosis are between the ages of 20 and 40. However, an MS diagnosis can come at any age, ranging from childhood to over 40.

Diagnosing MS currently can be challenging and time consuming. The diagnosis relies heavily on a person’s medical history and a physical neurological examination. Diagnostic testing is helpful in establishing the diagnosis of MS and ruling out other similar conditions.

If you’re experiencing symptoms that resemble MS, make an appointment with your doctor. The sooner you get diagnosed, the sooner you can get treatment, which can help to alleviate symptoms.

What labs are typically elevated for MS?

Lab tests are not typically the foundation of MS diagnosis because the blood test and CSF abnormalities in MS are also common with other inflammatory disorders, but people with MS may sometimes have:

  • high white blood cells in the blood
  • high oligoclonal bands, white blood cells, and protein in the CSF

Living with MS: Where to find support

It can also be helpful to talk with others who are going through the same thing. If you’d like to share advice and stories in a supportive environment, consider joining our MS Buddy community. The MS Buddy app is free and available for iPhone or Android.

Join Bezzy, a free MS community. With Bezzy, you’re never alone.