title: The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity.
abstract: OBJECTIVE
  To develop simple, practical criteria for clinical diagnosis of fibromyalgia that are suitable for use in primary and specialty care and that do not require a tender point examination, and to provide a severity scale for characteristic fibromyalgia symptoms.
  
  
  METHODS
  We performed a multicenter study of 829 previously diagnosed fibromyalgia patients and controls using physician physical and interview examinations, including a widespread pain index (WPI), a measure of the number of painful body regions. Random forest and recursive partitioning analyses were used to guide the development of a case definition of fibromyalgia, to develop criteria, and to construct a symptom severity (SS) scale.
  
  
  RESULTS
  Approximately 25% of fibromyalgia patients did not satisfy the American College of Rheumatology (ACR) 1990 classification criteria at the time of the study. The most important diagnostic variables were WPI and categorical scales for cognitive symptoms, unrefreshed sleep, fatigue, and number of somatic symptoms. The categorical scales were summed to create an SS scale. We combined the SS scale and the WPI to recommend a new case definition of fibromyalgia: (WPI > or =7 AND SS > or =5) OR (WPI 3-6 AND SS > or =9).
  
  
  CONCLUSIONS
  This simple clinical case definition of fibromyalgia correctly classifies 88.1% of cases classified by the ACR classification criteria, and does not require a physical or tender point examination. The SS scale enables assessment of fibromyalgia symptom severity in persons with current or previous fibromyalgia, and in those to whom the criteria have not been applied. It will be especially useful in the longitudinal evaluation of patients with marked symptom variability.
authors.affiliation: National Data Bank for Rheumatic Diseases and University of Kansas School of Medicine, Wichita, KS 67214, USA. fwolfe@arthritis-research.org
authors.forename: Frederick
authors.initials: F
authors.lastname: Wolfe
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Clauw
authors.forename: Mary-Ann
authors.initials: MA
authors.lastname: Fitzcharles
authors.forename: Don L
authors.initials: DL
authors.lastname: Goldenberg
authors.forename: Robert S
authors.initials: RS
authors.lastname: Katz
authors.forename: Philip
authors.initials: P
authors.lastname: Mease
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Russell
authors.forename: I Jon
authors.initials: IJ
authors.lastname: Russell
authors.forename: John B
authors.initials: JB
authors.lastname: Winfield
authors.forename: Muhammad B
authors.initials: MB
authors.lastname: Yunus
mesh_terms: D005356:Fibromyalgia / Q000145:classification* / Q000150:complications / Q000175:diagnosis; D006305:Health Status Indicators; D006801:Humans; D008490:Medical Informatics; D010146:Pain / Q000145:classification* / Q000150:complications / Q000175:diagnosis; D015203:Reproducibility of Results; D012219:Rheumatology / Q000592:standards*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012955:Societies, Medical; D014481:United States