Missing Anticitrullinated Protein Antibody Does Not Affect Short-term Outcomes in Early Inflammatory Arthritis: From the Canadian Early Arthritis Cohort.

OBJECTIVE: Anticitrullinated protein antibody (ACPA) is as sensitive as, but more specific than, rheumatoid factor (RF) and is detected earlier in rheumatoid arthritis (RA). Although part of the RA classification criteria, ACPA testing is not routinely paid for/accessible in all jurisdictions. The effect of missing ACPA testing was studied to determine whether failure to perform ACPA testing could cause a care gap in early inflammatory …