McDonald Criteria for MS

The 2010 Revised McDonald Diagnostic Criteria for MS are customarily used to determine a definitive diagnosis of MS. These criteria require the following combination of evidence for diagnosis: evidence of damage (clinical attacks and/or lesions) in 2 or more separate areas of the CNS (including the brain, spinal cord, and optic nerves), plus evidence that the damage happened 1 or more months apart, plus evidence that the damage did not happen because of another disease.

Evolution of diagnostic criteria

Diagnostic criteria for MS have evolved steadily over the last 5 decades, primarily due to advances in testing and imaging technologies. However, central to these criteria since the 1960s is the idea that evidence of CNS lesions must be disseminated in time (damage has to occur at least 1 month apart) and disseminated in space (damage has to affect at least 2 separate areas of the CNS). The original McDonald Criteria were developed in 2001, replacing earlier sets of diagnostic criteria (Schumacher Criteria and the Poser Criteria) in use before the era of magnetic resonance imaging (MRI). The McDonald Criteria specifically added the use of MRI, as well as analysis of cerebrospinal fluid (CSF), to establish diagnosis in cases where clinical evidence alone was not sufficient to support the diagnosis.

The table below presents 5 different scenarios in which MS can be diagnosed using 2010 Revised McDonald Diagnostic Criteria. Here are some useful definitions to help you understand information in the table.

MS attack. An MS attack, also called an exacerbation or relapse, is defined as a CNS disturbance typical of MS (either reported by the patient or observed by the doctor) that lasts at least 24 hours and must exclude the presence of infection or fever or other neurologic conditions that might explain the attack. Additionally, in some instances historical evidence of an event typical of an MS attack with evidence of demyelination can qualify as an attack. Individual attacks must be separated in time (the beginnings of each) by at least 30 days.

MRI evidence for dissemination in space. Evidence of dissemination in space includes at least one T2 MRI lesion in 2 out of 4 areas of the CNS, including 3 regions of the brain (periventricular, juxtacortical, infratentorial), or spinal cord. Use of gadolinium (Gd) enhancement on MRI is not required for evidence of dissemination in space. Lesions resulting from another neurologic disorder are excluded from the lesion count.

MRI evidence for dissemination in time. MRI evidence of dissemination in time includes new T2 or Gd-enhancing lesion(s) found on follow-up MRI or simultaneous finding of asymptomatic Gd-enhancing or other lesions on MRI at any time.

5 Different Scenarios for Diagnosing MS Under the 2010 McDonald Criteria


Clinical evidence

Additional supporting evidence from MRI or CSF

Dissemination in

Dissemination in

Time (How many attacks?)

Space (How many lesions?)

Time (How many attacks?)

Space (How many lesions?)

1. Clinical evidence alone

2 or more attacks2 or more lesions
1 lesion with historical evidence of prior attack
None needed None needed

2. Clinical evidence for time + clinical and MRI evidence for space

2 or more attacks1 lesionNone needed 1 or more T2 MRI lesion in 2 CNS regions typical in MS

3. Clinical evidence for space + clinical and MRI evidence for time

1 attack2 or more lesionsSimultaneous MRI lesions at any time
New T2 or Gd-enhancing MRI lesion(s) at follow-up
None needed

4. Clinical and MRI evidence for both time and space

1 attack1 lesionSimultaneous MRI lesions at any time
New T2 or Gd-enhancing MRI lesion(s) at follow-up
1 or more T2 MRI lesion in 2 CNS regions typical in MS

5. Only MRI and/or CSF evidence

NoneNone1 year of progressionAt least 2 out of following 3:
1. 1 or more T2 MRI lesion in 2 CNS regions typical in MS
2. 2 or more T2 MRI lesions in spinal cord
3. Positive CSF
Source: Polman CH, Reingold SC, Banwell B, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald criteria. Ann Neurol 2011;69:292-302.

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Written by: Jonathan Simmons | Last reviewed: May 2015.