Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition.

Although our results implicate a factor solution that best supports the CCC, revisions to the criteria are recommended.Implications for rehabilitationME/CFS is a chronic illness with no consensus regarding case diagnostic criteria, which creates difficulty for patients seeking assistance and disability benefits.The current study compared three commonly used case definitions for ME/CFS by factor analyzing symptomological data from an international sample of patients.Our results suggest three primary and four secondary symptom domains which differed from all three case definitions.These findings could help reduce barriers to care for those disabled with ME/CFS by guiding the development of an empirically-based case definition.