Need to improve the CDC Definitions

The 2003 Canadian definition is the most accurate definition so far—until one or more definitive diagnostic markers are found for ME/CFS. However, prior to the development of the Canadian definition, interest in improving the 1994 CDC definition was intense (for obvious reasons). Numbers of researchers are still working to improve the 1994 definition.

Because of the confusing and diagnostically porous nature of the 1994 Criteria, a number of the top international researchers most familiar with ME/CFS, decided to return to the earlier 1988 CDC CFS Criteria as a starting point for fashioning a suggested CFS symptom criteria with greater specificity in selecting CFS cases and in differentiating CFS from other fatiguing illness diagnoses.

There is no doubt that the 1988 (Holmes) CDC CFS Definition is more rigorous, selective and accurate in describing and defining the clusters of illness reported by various clinicians around the country than the 1994 CDC definition.

As it was more rigorous and selective, it was less open diagnostic confusion—the misdiagnosis of ME/CFS as another illness, and the diagnosis of other illnesses as ME/CFS. It should also be noted that, in many ways, the 1988 Criteria is a better guide to careful clinical investigation of the illness (except for the requirement that a diagnosis of CFS be excluded in the presence of anxiety disorder and some non-major mental illnesses).