Background/Purpose:

A positive anti-nuclear antibody (ANA) is considered very useful for the diagnosis of SLE and systemic sclerosis, and somewhat useful for the diagnosis of Sjögren’s syndrome and polymyositis/dermatomyositis. Higher the prior probability that a patient has a systemic autoimmune disease, the more likely the results of an ANA test will assist in establishing the diagnosis. However, ANA testing is ordered indiscriminately leading to high false positive results, increased unnecessary downstream testing and referral to rheumatology. ACR Choosing Wisely campaign in 2013 recommended not to test ANA sub-serologies without a positive ANA and clinical suspicion of immune-mediated disease. Our study aimed to study the adherence to these recommendations by residents in their outpatient primary care clinic of a community teaching hospital.

Methods:

Retrospective analysis of electronic medical records of patients seen by internal medicine residents in the primary care clinic during the duration of January 1, 2012 to December 31, 2016 was performed.The method of ANA testing used was EIA (Enzyme immunosorbent assay) . If positive ( > 1:80), reflex EIA for individual ANA sub serologies were performed. We analyzed the frequency of ANA ordering, reasons for ANA ordering and adherence to current ACR recommendations for subserology testing.

Results:

57 patients (out of total 757) had ANA tested during this period. Only 38/57(66%) had a documentation of strong clinical suspicion of an autoimmune disorder. 54 tests were complete at the time of data collection, two results were pending and one screen never completed. Of the 54 completed tests, 44/54 (81.5%) were negative and 10/54 (18.5%) were positive. The most common symptom for which ANA was ordered was joint pain 18/52 (34.6%) of which 5/18 patients had knee pain. In 9/54 patients (16.6%), ANA was ordered more than once (twice in 7 patients and thrice in 2 patients). Most common antibodies tested positive following a positive ANA were anti-double stranded DNA (anti-Ds DNA) in 5/10(50%) followed by anti-Jo1 antibody (antibody against anti-histidyl t RNA synthetase) 4/10(40%). Other antibodies positive were anti-c ANCA (1/10, 10%) and anti-SSA antibodies (1/10,10%). Most common diagnoses among the patients tested for ANA was osteoarthritis 7/54 (12.9%) followed by fibromyalgia (3/54,5.5%). 16/54 (29.6%) had no diagnosis. Among the 44 patients who were tested negative for ANA, 13/44 (29.5%) had other autoantibodies ordered.

Conclusion:

ANA testing was ordered without a strong clinical suspicion for a rheumatic/autoimmune disorder in 33% of patients. ANA was ordered more than once in 16.6% of the patients. Additional antibody testing was in 29.5% of patients with negative ANA in whom there was no clinical suspicion of a rheumatic/autoimmune disorder, which is against the “ACR Choosing Wisley recommendations”. Our study demonstrates that non-adherence to ACR recommendations for ordering ANA and ANA subserology testing is prevalent among trainees in the outpatient primary care setting. Educational and electronic medical record based interventions could be instituted to check this practice.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/are-residents-choosing-wisely-analysis-of-adherence-to-recommendations-of-ordering-anti-nuclear-antibody-testing-in-an-internal-medicine-residency-primary-care-clinic/