title: Limitations of the 1990 American College of Rheumatology classification criteria in the diagnosis of vasculitis.
abstract: BACKGROUND
  The American College of Rheumatology (ACR) established criteria to discriminate among patients with seven types of vasculitis. Although designated as "classification criteria" for research, these criteria are often used for diagnosis.
  
  
  OBJECTIVE
  To examine the operating characteristics of the 1990 ACR classification criteria in the diagnosis of Wegener granulomatosis, giant-cell arteritis, polyarteritis nodosa, and hypersensitivity vasculitis.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  University medical center and Veterans Affairs medical center.
  
  
  METHODS
  198 consecutive patients referred to rheumatologists for evaluation of possible vasculitis.
  
  
  METHODS
  Blinded chart audits were done to classify patients according to the 1990 ACR classification criteria for Wegener granulomatosis, polyarteritis nodosa, giant-cell arteritis, and hypersensitivity vasculitis on the basis of the patients' initial presentation. Chart audits done 2 to 8 months after baseline provided the patients' final diagnoses, which were considered the gold standard, as in the development of the ACR criteria. Test operating characteristics of the ACR classification criteria were calculated according to 2 x 2 tables for the entire cohort and for only the patients with a final diagnosis of vasculitis.
  
  
  RESULTS
  Vasculitis was diagnosed in 51 (26%) patients. Thirty-eight (75%) of 51 patients with vasculitis and 31 (21%) of 147 patients without vasculitis met ACR criteria for one or more types of vasculitis. The positive predictive values for the four vasculitides according to ACR criteria were 17% to 29% for the entire cohort and 29% to 75% for only the patients with a final diagnosis of vasculitis.
  
  
  CONCLUSIONS
  The 1990 ACR classification criteria function poorly in the diagnosis of specific vasculitides.
authors.affiliation: Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana 46202, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Rao
authors.forename: N B
authors.initials: NB
authors.lastname: Allen
authors.forename: T
authors.initials: T
authors.lastname: Pincus
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D013700:Giant Cell Arteritis / Q000175:diagnosis; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010488:Polyarteritis Nodosa / Q000175:diagnosis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D014657:Vasculitis / Q000145:classification / Q000175:diagnosis*; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000175:diagnosis