Case definition of ME/CFS

U.S. Case Definition of Chronic Fatigue Syndrome is defined by Fukuda et al. (Ann Intern Med, 121:953-9, 1994). It has to two major features, and both have to be present simultaneously:
1. Medically unexplained chronic fatigue, experienced for at least six months;
a) Which is of new or definite onset (has not been lifelong)
b) That is not substantially alleviated by rest
c) That is not the result of ongoing exertion
d) That results in substantial reduction in occupational, educational, social, or personal activities
2. Concurrent occurrence of four or more of the following symptoms, which must be persistent or recurrent during six or more months of the illness and do not predate the fatigue:
a) Unrefreshing sleep
b) Exacerbation of fatigue by exertion
c) Self-reported persistent or recurrent impairment in short-term memory or concentration severe enough to cause substantial reductions in previous levels of occupational, social, or personal activities
d) Muscle pain
e) Multiple joint pain without joint swelling or redness
f) Headaches of new type, pattern, or severity
g) Sore throat
h) Tender cervical or axillary lymph nodes
The criteria that are mainly used today are the Canadian Clinical Criteria which are developed by Health Canada (Carruthers et al, 2003).These guidance is intended to provide a clinical definition that places greater emphasis on a disease that equates with neuroimmune dysfunction.
Still another group of criteria are The International Consensus Criteria (ICC), where efforts are made to further sharpen the delimitation of ME/CFS. In our research we use the Canadian Criteria in combination with the Fukuda Criteria.

Diagnostic tools
The diagnosis of FM is based on digital palpation of tender points and on the patient history. ME/CFS is only based on the patient history. The diagnoses can be easily made by any interested GP.
There is no specific laboratory test to support the diagnosis of FM or ME/CFS.