RT Journal Article
SR Electronic
T1 Clinical and Serological Analysis of Patients with Positive Anticyclic Citrullinated Peptide Antibodies Referred Through a Rheumatology Central Triage System
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP jrheum.141054
DO 10.3899/jrheum.141054
A1 Liam Martin
A1 Whitney A.  Steber
A1 Terri L.  Lupton
A1 Michael Mahler
A1 Christie M.  Fitch
A1 Jacob D.  McMillan
A1 Danielle R.  Schmidt
A1 Marvin J.  Fritzler
YR 2015
UL http://www.jrheum.org/content/early/2015/01/27/jrheum.141054.abstract
AB Objective Anticitrullinated protein antibodies (ACPA) are a highly specific and sensitive biomarker for the diagnosis of rheumatoid arthritis (RA). Some patients who were found to have a positive ACPA test were referred to our Rheumatology Central Triage (CT; Calgary, Alberta, Canada) for assessment by a rheumatologist. The objectives of our study were to determine the clinical accuracy of ACPA in establishing a diagnosis of RA in a real-time clinical setting. Methods Cases that met 3 criteria were included in the study: (1) referred to the CT over 3 calendar years (n = 20,389), (2) reason for referral was a positive ACPA test (n = 568), and (3) evaluated by a certified rheumatologist (n = 314). An administrative serological database was used to retrieve specific ACPA results. Results Of patients referred through our CT for evaluation of a positive ACPA test, 57.6% received a diagnosis of RA; the remainder had a variety of other diagnoses, some of which might be considered early RA (9%). The predictive values of ACPA for the diagnosis of RA were increased when rheumatoid factor (RF) results were included in the analysis. When definite and possible RA were combined and the prevalence of moderate/high ACPA was compared to all other individuals, the positive and negative predictive values for moderate/high ACPA for RA were 74.3% and 68.4%, respectively. Conclusion About 58% of patients with a positive ACPA referred through a triage system for a rheumatologist opinion received a diagnosis of RA at their first visit. RF provides additional useful information to guide the diagnosis and urgency of referral.