What is Necessary to Receive a Correct and Accurate Diagnosis of An Illness?

Before any illness can be diagnosed, medical science must provide an accurate "case definition" for the illness—a definition that correctly describes the signs, symptoms, illness progression, pathophysiology (deleterious effects of the illness on the body), laboratory abnormalities, and known causal agents. Second, this "case definition" must distinguish the specific illness from other known illnesses—otherwise a specific illness would not be distinguishable from other illnesses, and a diagnosis of it would be impossible.

The preceding discussion is necessary because there has been much confusion and disagreement as to what the illness CFIDS/CFS/ME actually is. Not only is the illness known by various names: Chronic Fatigue Syndrome (CFS), Chronic Fatigue Immune Dysfunction Syndrome (CFIDS), Myalgic Encephalopathy and Myalgic Encephalomyelitis (ME), but there are several different case definitions that describe the illness somewhat differently and provide different diagnostic criteria. Because the illness first became widely identified in the mid-1980s, a number of case definitions and diagnostic criteria were developed as physicians and researchers learned more about the illness.

Therefore patients and physicians would benefit from knowing which case definitions and diagnostic criteria for the actual illness are the most scientifically and medically accurate.

In order to obtain a diagnosis of CFS/CFIDS/ME, the patient must see a physician who is sufficiently knowledgeable to evaluate the illness according to CFS/CFIDS/ME diagnostic criteria. We feel the 2003 Canadian definition is the most accurate of the various criteria sets available.

If one has Fibromyalgia (FM), the situation is more fortunate in terms of diagnostic criteria. The 1990 U.S. College of Rheumatology diagnostic criteria are short and straightforward:

• Widespread pain for at least 3 months.
• Pain in all four quadrants of the body: right side, left side, above and below the waist.
• Pain in at least 11 of 18 specified tender points when they are pressed. These 18 sites cluster around the neck, shoulder, chest, hip, knee, and elbow regions.

No exclusions are made for the presence of concomitant radiographic or laboratory abnormalities.