Value of laboratory tests in early prediction of rheumatoid arthritis.
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.
Saraux
Alain
A
Rheumatology Unit, Hôpital de la Cavale Blanche, Brest, France. Alain.Saraux@univ-brest.fr
Berthelot
Jean M
JM
Chalès
Gérard
G
Le Henaff
Catherine
C
Mary
Jean Y
JY
Thorel
Jean B
JB
Hoang
Sylvie
S
Dueymes
Maryvonne
M
Allain
Jérôme
J
Devauchelle
Valerie
V
Baron
Dominique
D
Le Goff
Paul
P
Youinou
Pierre
P
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
D001323:Autoantibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007633:Keratins; D012217:Rheumatoid Factor