There are currently no tests specifically to diagnose multiple sclerosis (MS). However, scans, blood tests, and other assessments can help identify and monitor the condition and rule out other causes of symptoms.

Doctors use several strategies to check whether a person’s symptoms meet the criteria for an MS diagnosis. Before making a diagnosis, a doctor needs to exclude the possibility of other conditions. To do this, they may use MRIs, blood tests, and spinal fluid analysis.

When a person has MS, their immune system attacks myelin, which covers and protects the nerve cells. When the myelin has become damaged, scar tissue — or sclerosis — develops. This then interrupts the nerve’s ability to send and receive messages.

For some people, treating MS can help manage the condition and slow the progression of symptoms. For this reason, it is advisable to seek diagnosis as early as possible.

In this article, we look at the various strategies a doctor might use to diagnose MS.

For more information about MS, visit our dedicated hub.

blood tests to rule out conditions other than MSShare on Pinterest
solarseven/Getty Images

When diagnosing MS, a doctor will consider factors known as dissemination in space (DIS) and dissemination in time (DIT).

DIS focuses on the parts of the body that MS has affected, and DIT charts the progression of the condition over time.

For DIS, doctors will look at an MRI scan for at least two different lesions that are characteristic of MS, or one lesion and one clinical attack affecting a different part of the central nervous system.

For DIT, they will look for evidence of one of the following:

  • two or more clinical attacks separated by time
  • the presence at one time of one MRI-enhancing and one non-enhancing lesion specific to MS
  • one MS-specific MRI lesion at baseline and a new lesion on a follow-up MRI
  • specific cerebrospinal fluid (CSF) findings

Enhancing lesions specific to MS are active lesions exhibiting severe inflammation and breaking down of the blood-brain barrier. By contrast, non-enhancing lesions in MS are chronic and do not increase in intensity.

Currently, no single test can identify MS, and the condition can be challenging to diagnose. A doctor will start by:

  • reviewing a person’s symptoms
  • carrying out a physical examination
  • asking about their personal and family medical history

They may do tests to help assess the person’s:

  • language functions and speech
  • movement, coordination, and balance
  • vision, smell, taste, touch, and hearing
  • emotional and psychological well-being

The following diagnostic tests may also help confirm the diagnosis by identifying lesions and ruling out other possible causes of symptoms.


MS can cause scar tissue, or plaques, to develop on damaged nerves. An MRI allows the doctor to look for this scar tissue.

If a person has these unusual spots, or lesions, they will not necessarily have MS. These can sometimes indicate other conditions, such as migraine or high blood pressure.

When a person has MS, myelin becomes inflamed, leading to microscopic injury. This injury is visible on an MRI scan.

A doctor must carefully examine an MRI scan to diagnose MS accurately.

Evoked potentials

An evoked potential test is an electrical test of the nerve pathways. It can help a doctor determine which nerve pathways have incurred damage from MS.

The doctor will place wires on a person’s scalp and examine the brain’s response to specific experiences, such as:

  • watching a video screen
  • hearing a particular sound
  • feeling certain sensations

Although the test is highly sensitive, it is harmless and typically painless.

Damaged myelin slows electrical conduction along nerve pathways.

Lumbar puncture

A lumbar puncture enables a doctor to obtain CSF for analysis. This can help rule out other causes of symptoms.

To extract CSF, the doctor inserts a needle between bones in the lower spine. They withdraw fluid using a syringe and then test for antibodies and proteins that may signal an atypical immune response, such as oligoclonal bands.

Doctors no longer use lumbar puncture as a first-line test. An experienced doctor will decide whether a lumbar puncture is necessary based on medical history and the outcome of a physical examination.

Blood testing

Blood tests cannot diagnose MS, but they can help rule out other conditions with similar symptoms, such as:

  • Lyme disease
  • HIV
  • syphilis
  • metabolic conditions that cause vitamin deficiencies
  • some inflammatory and autoimmune conditions, such as sarcoidosis, Sjögren’s disease, and systemic lupus erythematosus, also known as lupus
  • some genetic conditions, such as Fabry disease

Eye scan

While not part of the doctor’s standard diagnostic toolkit for MS, an eye scan known as optical coherence tomography (OCT) can help pick up some early signs.

OCT scanning technology uses light echoes to “see” into eye tissues, in a similar way that ultrasound uses sound echoes.

OCT has enabled experts to gain direct images of nerves and cells in the retina. It can also show whether demyelination is due to MS or neuromyelitis optica, another cause of vision problems.

When to contact a doctor

Anyone who suspects they may have symptoms of MS should seek medical advice.

The first sign is often vision changes, for instance:

  • double vision
  • vision loss in one eye
  • distortion between red and green

Weakness, numbness, and tingling may also be early signs.

It is essential to seek medical help as soon as possible, as early treatment may help slow the progression of MS.

Most people experience their first symptoms of MS between the ages of 20 and 40 years. Vision changes are often the first sign.

According to the Multiple Sclerosis Foundation, early signs and symptoms include:

  • numbness and tingling in the feet, legs, hands, arms, or face
  • vision problems, such as blurry or double vision, loss of vision or color contrast, and pain when moving the eye
  • fatigue
  • difficulty walking
  • bladder problems
  • sexual difficulties, for example, reduced sex drive or erectile dysfunction
  • problems with memory or speech
  • depression and emotional changes
  • muscle spasms and tremors

However, symptoms vary from person to person and may change over the course of the condition. Symptoms can also depend on which nerves develop plaques and incur damage.

If any of these symptoms occur regularly, a person should seek an evaluation with an MS specialist.

Here, learn more about the early signs of MS.

There is currently no cure for MS and no single treatment. A person will likely need a wide-ranging approach to managing the symptoms and slowing progression of the condition.

Strategies include:

  • disease-modifying therapies, which involve drugs that may slow the progression of the condition and reduce the severity of relapses
  • steroid medications to treat severe symptoms during a relapse
  • treatment for specific symptoms, such as muscle relaxants to reduce muscle stiffness, known as spasticity
  • physical therapy to help preserve mobility and learn how to use aids, such as a walking cane
  • counseling to help manage the impact on mental well-being

A person will usually work with a healthcare team of different specialists to manage their condition.

Here, find more details on treating and managing MS.

MS is a progressive condition that affects individuals differently. In most cases, symptoms will come and go. Many people experience times of relapse and then periods of remission, when symptoms improve or disappear.

Treatment aims to:

  • reduce the frequency and severity of attacks
  • manage pain, discomfort, and other symptoms during a relapse
  • keep the person mobile and active
  • preserve the person’s quality of life

Many people continue to live a full and active life with MS. It is not life threatening, but severe complications can sometimes arise, such as chest or bladder infections. In some cases, it can lead to disability and mobility issues.

Research from 2017 suggests that life expectancy for a person with MS is around 7 years lower than for those without the condition. However, the gap is closing.

How does MS affect life expectancy?

The following are answers to commonly asked questions about MS.

What is the first indicator of MS?

Early symptoms of MS include balance problems, difficulty walking, fatigue, and blurred vision.

Is multiple sclerosis hard to diagnose?

Yes, MS can be difficult to diagnose. This is because no single test can diagnose the condition. A doctor will review a person’s symptoms, carry out a physical exam, and order further tests.

What age is MS usually diagnosed?

MS is most commonly diagnosed between ages 20 and 40.

Does MS show up on MRI?

Yes, MS can show up on an MRI. The condition causes scar tissue to develop on damaged nerves, and seeing these in an MRI scan means a person might have MS.

There is no specific test to diagnose MS, but doctors will consider various factors, such as the number and types of attack a person has had, any lesions that show up on an MRI scan, and results of other tests to rule out other conditions.

If a doctor diagnoses MS, they may recommend long-term treatment with disease-modifying therapies, which can help reduce the frequency and severity of relapses.