title: Study findings challenge the content validity of the Canadian Consensus Criteria for adolescent chronic fatigue syndrome.
abstract: OBJECTIVE
  The 2003 Canadian Consensus Criteria for chronic fatigue syndrome (CFS) are often assumed to suggest low-grade systemic inflammation, but have never been formally validated. This study explored the content validity of the Criteria in a sample of adolescents with CFS selected according to a wide case definition.
  
  
  METHODS
  A total of 120 patients with CFS with a mean age of 15.4 years (range 12-18 years) included in the NorCAPITAL project were post hoc subgrouped according to the Canadian Consensus Criteria. Those who satisfied the criteria (Criteria positive) and those who did not (Criteria negative) were compared across a wide range of disease markers and markers of prognosis.
  
  
  RESULTS
  A total of 46 patients were classified as Criteria positive, 69 were classified as Criteria negative, and five could not be classified. All disease markers were equal across the two groups, except the digit span backward test of cognitive function, which showed poorer performance in the Criteria-positive group. Also, the prognosis over a 30-week period was equal between the groups.
  
  
  CONCLUSIONS
  This study questions the content validity of the Canadian Consensus Criteria, as few differences were found between adolescent patients with CFS who did and did not satisfy the Criteria.
authors: Division of Medicine and Laboratory Sciences, Medical Faculty, University of Oslo, Oslo, Norway.
authors: Tarjei Tørre
authors: TT
authors: Asprusten
authors: Even
authors: E
authors: Fagermoen
authors: Dag
authors: D
authors: Sulheim
authors: Eva
authors: E
authors: Skovlund
authors: Øystein
authors: Ø
authors: Sørensen
authors: Tom Eirik
authors: TE
authors: Mollnes
authors: Vegard Bruun
authors: VB
authors: Wyller
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003071:Cognition; D015444:Exercise; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000378:metabolism / Q000523:psychology; D011795:Surveys and Questionnaires; D003245:Consensus Statements as Topic
chemical_list: D015415:Biomarkers
keywords: Adolescence; Chronic fatigue syndrome; Cytokines; Diagnostic criteria; Validity