The diagnosis of multiple sclerosis (MS) is based on clinical expertise of a board certified neurologist.  There are certain criteria observed that have evolved over time from Schumacher, to Poser, to currently McDonald. Clinicians must evaluate the characteristic age of onset, clinical pattern, history, and neurologic findings typical of MS. Criteria also require that changes in the central nervous system must be separated in space and time and not just occur one time only.

Ultimately, MS is a clinical diagnosis because, while there are many laboratory tests, there is no ONE definitive test that firmly establishes the certainty of the disease. Even so, it is somewhat disturbing that there are still people who have been misdiagnosed with MS. Therefore it is important that this conclusion be made by an MS specialist.

Clinical features that suggest MS include the age of onset which is typically between the ages of 15 and 50 years. It affects women in greater proportion than men. The less common presentation is in an older man or woman with gradual development of neurologic problems (progressive form). The more common presentation is with symptoms which are episodic and spontaneously improve (relapsing-remitting).  The least common is the diagnosis in children (called pediatric MS). This type of MS is becoming more widely recognized in the medical community during recent years.

Diagnostic Criteria

The clinical profile for MS requires symptomatic disease activity over time (not occurring just once and never again) and confirmed by an objective neurologic  eamination. The more common symptoms are numbness, paresthesias (strange sensations in the body), pain, motor abnormalities, and visual problems.

Diagnosis is usually made by a neurologist after a person has experienced two or more attacks that can be traced to changes in the CNS. According to the current diagnostic criteria, attacks should be separated by at least one month and should last 24 hours or more. These attacks should occur independently of any other disease or condition.

After symptoms occur that appear to be MS, findings of the neurologic examination must establish that these changes originate in the brain, spinal cord or both. Neurologic findings cause the first note of suspicion that the problem is MS.   

An examination by the neurologist should confirm that there are changes in the CNS indicating MS. In addition, a history should be obtained from the patient or family indicating any past damage to the CNS. Information such as birthplace, age, when symptoms first began, and the nature of the symptoms helps the neurologist determine if MS is a possible diagnosis.


Laboratory testing is very important to assist in the diagnostic process. Magnetic resonance imaging (MRI) is a key test in this process. MS lesions on MRI have specific locations, size and shape and can support the neurologist’s opinion about the diagnosis.

Other tests such as blood work, evoked potential testing (which determines the speed of nerve conduction) and lumbar puncture can facilitate informed decisions by the neurologist.

Learn more about tests for MS.

MS Characterization

The course of the disease, once the diagnosis is established, can be categorized into:

  • relapsing-remitting (attacks and recovery)
  • secondary progressive (relapsing MS that changes to a worsening form with little or no recovery)
  • primary progressive (gradual worsening with no recovery)
  • progressive relapsing (worsening with occasional relapses).

The latter three of these classifications begin as relapsing forms of MS but over time, there may be conversion to a progressive course. This is unpredictable at the outset of the disease. About 10 percent of people with MS have a primary-progressive course that worsens continually from the outset.

Until the latter part of the 20th century, it took months and occasionally years to diagnose MS. With the advent of new technology, particularly MRI, the diagnosis can be made more promptly by physicians with an expertise in multiple sclerosis.