Applying Choosing Wisely: Antinuclear Antibody (ANA) and Sub-Serology Testing in a Safety Net Hospital System

OBJECTIVE: In 2013, the American College of Rheumatology (ACR) participated in the Choosing Wisely campaign and devised a recommendation to avoid testing antinuclear antibody (ANA) subserologies without a positive ANA and clinical suspicion of disease. The goals of our study were to describe ANA and subserology ordering practices and predictors of ordering concurrent ANA and subserologies in a safety-net hospital. METHODS: We identified ANA and subserologies (dsDNA, Sm, RNP, SSA, SSB, Scl-70 and centromere) completed at Denver Health between 1/1/2005 and 12/31/2011. Variables included demographics, primary insurance, service, and setting from which the test was ordered. We performed multivariable logistic regression to determine predictors of concurrent ordering of ANA and subserologies. RESULTS: During seven years, 3221 ANA were performed in 2771 individuals and 211 (6.6%) were performed concurrently with at least one subserology. The most common concurrent subserologies were dsDNA (21.8%), SSA (20.8%), and SSB (19.7%). In the multivariable logistic analysis, significant predictors of concurrent ANA and subserologies were the labs being ordered from subspecialty care (OR 8.12, 95% CI 5.27-12.50, p-value <0.0001) or from urgent/inpatient care (OR 3.86, 95% CI 1.78-8.38, p-value 0.001). A significant predictor of decreased odds was male gender (OR 0.32, 95% CI 0.21-0.49, p-value <0.0001). Five individuals (2.2% of the negative ANA with subserologies ordered) had a negative ANA but positive subserologies. CONCLUSION: Of 3221 ANA, 6.6% were performed concurrently with subserologies, and subspecialists were more likely to order concurrent tests. A negative ANA predicted negative subserologies with rare exceptions, which validates the ACR’s recommendations.