Article Index

The Canadian Definition and Diagnostic Criteria

The Diagnostic Protocol includes the "Clinical Working Case Definition"; a section on "Applying the Case Definition to the Individual Patient"; a "Discussion of the Major Features of ME/CFS"; "Features of ME/CFS in Children"; a guide for the "Clinical Evaluation of ME/CFS", which includes procedures for taking a patient history and for conducting the physical examination; the "Laboratory and Investigative Protocol" (general and more specialized lab tests); sections on differential diagnoses; along with a section on prognosis and disability assessment.

The entire diagnostic and case protocol is an extensive 22 pages, and requires careful reading. We will present a brief summary here with the hope of making the full document more accessible.

The first section contains the actual signs and symptoms criteria by which a patient achieves a diagnosis after other excluding illnesses are eliminated. Throughout, the definition makes clear that this clustering of symptoms, symptom-complexes, and pathophysiological signs is not random or disorganized, but is a coherent and recognizable cluster pattern of a specific and identifiable disease syndrome. As an analogy—before the nature and possible causes of Multiple Sclerosis (MS) were discovered, medical science identified MS primarily through its (unfortunately) reproducible symptoms.