Background/Purpose: The American College of Rheumatology (ACR) was asked by the American Board of Internal Medicine to contribute to the “Choosing Wisely” campaign.  The first recommendation from the ACR was: Don’t test Antinuclear Antibody (ANA) subserologies without a positive ANA and clinical suspicion of immune-mediated disease. Rheumatologists likely presume that non-rheumatologists often use a “shotgun” approach when ordering ANA and subserologies.  However, we wanted to look at how often physicians including rheumatologists used this “shotgun” approach that the ACR cautions against.  We also investigated the clinical relevance of a positive subserology when the ANA is negative and the financial impact of such shotgun testing.

Methods: We conducted a retrospective study of the Geisinger integrated health system that examined ANA and subserology ordering practices of all physicians.  Data from 2010-2012 was collected from the EPIC electronic health record and Sunquest lab system.  We reviewed physician serology ordering rationale to determine the relevance of positive subserology when the ANA was negative.  Subserologies included were DSDNA, Anti-Smith, RNP, SSA/SSB, SCL70 and JO1. We classified the reasoning for ordering a subserology prior to knowledge of ANA result as either justified or not justified.  The subserology was justified if there was a high clinical suspicion of a specific systemic autoimmune inflammatory disease whose associated subserology is not included in the screening ANA (i.e. SSA/SSB. JO1 AB).  Finally, we completed a 2010-12 cost analysis for unjustified subserology ordering.

Results: Of the 51 patients with negative ANA and a positive subserology, 41 had positive SSA/SSB, 7 Anti-Smith, 5 RNP, 2 SCL70, 0 JO1, and 0 DSDNA.   51% (26/51) of the patients had subserology orders placed by a rheumatologist at the same time as the ANA, prior to ANA results.  22% (11/51) had testing ordered by Neurologists and the other 27% (14/51) were ordered by primary physicians and other specialties.  75% of the patients had both ANA and subserology testing ordered concurrently.  75% of cases had unjustified reasoning for the subserology order.  Positive subserologies when the ANA was negative did not have any clinical relevance. The cost analysis showed an average cost of tests ordered at $631.00 per patient totaling $32843 for all 51 patients.  This was a small fraction of the total cost of all unjustified subserologies ordered, if one includes the NEGATIVE subserologies when the ANA was negative.

Conclusion:  Rheumatologists do not always “practice what we preach.” Rheumatologists ordered the majority of unjustified subserologies.  We have demonstrated that there is significant waste of healthcare resources by the inappropriate ordering of subserologies, and that most of that waste is by rheumatologists. Positive subserologies when the ANA was negative did not have clinical importance. Of interest, we discovered that the ANA by Enzyme Linked Immunosorbent Assay (ELISA) assays and the subserology ELISA assays used by our lab were from two different manufacturers.  The methodology difference could explain the positive subserology tests in patients with negative ANA’s.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/do-rheumatologists-and-other-specialists-practice-what-we-preach-a-study-of-serology-ordering-patterns-with-attention-to-subserologies-when-the-antinuclear-antibody-by-enzyme-linked-immunosor/