title: Value of laboratory tests in early prediction of rheumatoid arthritis.
abstract: OBJECTIVE
  To determine which laboratory test or tests at presentation best predicted a diagnosis of rheumatoid arthritis (RA) 2 years later.
  
  
  METHODS
  Two hundred seventy patients with early arthritis seen in 7 hospitals underwent comprehensive evaluations at 6-month intervals for 2 years, when the diagnosis of RA was assessed by 5 rheumatologists. The sensitivity and specificity of each test at the first visit for discriminating between RA (38%, n = 98) and non-RA patients were determined. Optimal cutoffs for continuous tests were derived from receiver operating characteristic curves. Sensitivity and specificity of test combinations selected by multiple logistic regression were determined.
  
  
  RESULTS
  IgM rheumatoid factor (RF) by enzyme-linked immunosorbent assay, IgG-antikeratin antibody (AKA), and latex test had the strongest associations with RA. These 3 tests formed the most powerful combination for distinguishing RA from non-RA.
  
  
  CONCLUSIONS
  IgM-RF, IgG-AKA, and the latex test are the best laboratory tests for discriminating between patients with and without RA. Combining these tests slightly improves diagnostic value.
authors.affiliation: Rheumatology Unit, Hôpital de la Cavale Blanche, Brest, France. Alain.Saraux@univ-brest.fr
authors.forename: Alain
authors.initials: A
authors.lastname: Saraux
authors.forename: Jean M
authors.initials: JM
authors.lastname: Berthelot
authors.forename: Gérard
authors.initials: G
authors.lastname: Chalès
authors.forename: Catherine
authors.initials: C
authors.lastname: Le Henaff
authors.forename: Jean Y
authors.initials: JY
authors.lastname: Mary
authors.forename: Jean B
authors.initials: JB
authors.lastname: Thorel
authors.forename: Sylvie
authors.initials: S
authors.lastname: Hoang
authors.forename: Maryvonne
authors.initials: M
authors.lastname: Dueymes
authors.forename: Jérôme
authors.initials: J
authors.lastname: Allain
authors.forename: Valerie
authors.initials: V
authors.lastname: Devauchelle
authors.forename: Dominique
authors.initials: D
authors.lastname: Baron
authors.forename: Paul
authors.initials: P
authors.lastname: Le Goff
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
mesh_terms: D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D001323:Autoantibodies / Q000097:blood; D019411:Clinical Laboratory Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007633:Keratins / Q000276:immunology; D007841:Latex Fixation Tests; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012044:Regression Analysis; D012217:Rheumatoid Factor / Q000097:blood; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007633:Keratins; D012217:Rheumatoid Factor