McDonald Criteria

In brief: The McDonald criteria are specialist diagnostic criteria that organize evidence for multiple sclerosis in an appropriate clinical or radiologic context.

Use in multiple sclerosis

The criteria combine evidence that characteristic central nervous system lesions are distributed across relevant locations and, when required, across time. Clinical attacks, MRI findings, cerebrospinal fluid markers, and optic nerve evidence can contribute in defined combinations.

The 2024 revision adds the optic nerve as a fifth anatomical location and introduces roles for the central vein sign, paramagnetic rim lesions, and kappa free light chains. It also addresses selected radiologically isolated presentations and age-specific safeguards. [1]

Meeting a checklist does not remove the requirement for a compatible context and no better explanation. Nonspecific symptoms or white-matter spots should not be forced into the criteria.

Clinical detail

Diagnostic criteria optimize consistency; they do not replace differential diagnosis. Performance depends on patient selection, MRI quality, biomarker methods, and faithful application of required exclusions.