McDonald Criteria for Multiple Sclerosis (2017 Revision)

McDonald Criteria (2017): Clinical attacks* Number of lesions with objective clinical evidence** Additional data needed for diagnosis of MS ≥2 ≥2 No additional tests required to demonstrate dissemination in space and time 1 (as well as clear-cut historical evidence of a previous attack involving a lesion in a distinct anatomical location) No additional tests required to demonstrate dissemination in space and time 1 Dissemination in space demonstrated by an additional clinical attack implicating a different CNS site or by MRI 1 ≥2 Dissemination in time demonstrated by additional clinical attack or MRI, or presence of CSF-specific oligoclonal bands 1 Dissemination in space demonstrated by an additional clinical attack implicating a different CNS site or by MRI and dissemination in time demonstrated by additional clinical attack or MRI, or presence of CSF-specific oligoclonal bands *“Clinical attack” = monophasic clinical episode with patient-reported symptoms and objective findings reflecting inflammatory demyelinating CNS event (focal or multifocal), subacute or acute, for ≥24 hrs, with or without recovery, and no fever or infection present. Attack, relapse, exacerbation, and clinically isolated syndrome (first episode) are all synonymous. **“Objective clinical evidence” = abnormality on neurologic exam, imaging (MRI or optical coherence tomography), or visual evoked potentials, corresponding to anatomical location suggested by symptoms.