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Diagnosing multiple sclerosis (MS)

There is no single test to diagnose MS, but a neurologist will make a multiple sclerosis diagnosis based on a patient's symptoms, a neurological examination and other diagnostic tests.

Other medical conditions cause similar symptoms to those of MS, and these may have to be ruled out first.

A firm MS diagnosis may not be made after an initial MS ‘attack’. In relapsing-remitting MS, symptoms often go away, but may return at a later stage.

MS early warning signs

You should seek medical advice if you have any of the signs and symptoms associated with multiple sclerosis (MS).
Several of the symptoms of MS may require you to be seen at a hospital's accident and emergency (A&E) department.

  • If you experience visual changes and painful eye movements, go to the nearest A&E department. You could have optic neuritis, one of the most common early signs of MS. If you can be treated with corticosteroid medication shortly after optic neuritis develops, the course of the disease may be altered.
  • If you have changes in personality, sudden loss of strength in the arms and legs, or respiratory difficulty, you should go to the A&E department for evaluation. These symptoms are common with MS, but they can also be signs of other serious diseases, such as stroke, infection, or chemical imbalances.

How is an MS diagnosis made?

An accurate diagnosis is based on your medical history and a neurological examination, physical examination and asking about symptoms.

Additional tests may be arranged:


More than 9 out of 10 MS diagnoses are made after an MRI scan which gives doctors detailed images of the brain and spinal cord.

The scan may show plaques, scarring or damage to the protective myelin coating around nerves.

Evoked potentials test

The evoked potentials test uses electrodes on the head to check how quickly brain waves respond to sights or sounds. If the brain takes longer than normal to receive messages, it may indicate MS nerve damage.

Lumbar puncture

A lumbar puncture, or spinal tap, may be arranged if other tests are inconclusive.

A special needle is used to take a sample of cerebrospinal fluid from around the spinal cord under local anaesthetic.

The fluid sample is tested for antibodies which would show whether the body has been fighting any infection in the central nervous system.

What other tests are performed?

A doctor may arrange a blood test to help rule out conditions that have similar symptoms to multiple sclerosis.

Different types of multiple sclerosis

As well as diagnosis of MS itself, further work will be done to assess the type of MS. However, this may take some years, depending on the progression of symptoms.

Relapsing-remitting MS diagnosis:

  • Two relapses of symptoms longer than 30 days apart
  • One relapse and an MRI scan showing new myelin damage or scarring 3 months later

Secondary progressive multiple sclerosis (SPMS):

  • Past relapses of symptoms
  • Progressive onset of disabling symptoms over at least 6 months, with or without relapses

Primary progressive multiple sclerosis (PPMS)

No previous relapses of symptoms, and:

  • The person has become progressively more disabled for at least a year
  • MRI scan shows myelin damage and scarring
  • Lumbar puncture detects antibodies

After an MS diagnosis

A diagnosis of MS changes a person's life. Everyone's symptoms and disease progression will be different and managed by an MS healthcare team, which usually includes a neurologist and specialist MS nurses.

Decisions will be made about long-term treatment to help prevent and control symptoms and changes may be needed to daily life.

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on September 26, 2017

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