McDonald Criteria

The McDonald criteria are diagnostic criteria for multiple sclerosis (MS). These criteria are named after neurologist W. Ian McDonald. In April 2001, an international panel in association with the National Multiple Sclerosis Society (NMSS) of America recommended revised diagnostic criteria for MS. They discourage the previously used terms such as "clinically definite" and "probable MS", and propose as diagnostic either "MS", "possible MS", or "not MS".

They make use of advances in magnetic resonance imaging (MRI) techniques and are intended to replace the Poser criteria and the older Schumacher criteria. The new criteria facilitate the diagnosis of MS in patients who present with signs and symptoms suggestive of the disease. These include monosymptomatic disease, disease with a typical relapsing-remitting course or insidious progression but no clear attacks and remissions.

The McDonald criteria for the diagnosis of multiple sclerosis were revised in 2005 to clarify exactly what is meant by an "attack". "dissemination". a "positive MRI", etc.

Any diagnostic criterion relies on definition or another more basic criterion. The original article of McDonald states that "MS is a clinical entity and therefore should be diagnosized with clinical and paraclinical criteria". Nevertheless, they acknowledge the existence of lesion-based MS definition, saying that some other groups consider that "the only proved diagnosis of MS can be made upon autopsy, or occasionally upon biopsy, where lesions typical of MS can be directly detected through standard histopathological techniques".

Currently, the McDonald criteria are regarded as the gold standard for MS diagnosis.