Antibodies to peptides not currently used for rheumatoid arthritis (RA) diagnosis helped identify patients with untreated early disease that conventional biomarkers missed, researchers said.

Almost two-thirds of blood samples from some 2,100 patients with early RA (63%) tested positive on a panel of five such antibodies in a preliminary test, with a specificity of 99% and an area under the receiver operating characteristic curve (AUC) of 83% for overall accuracy, reported Rikard Holmdahl, MD, PhD, of the Karolinska Institute in Stockholm, and colleagues.