1278: ANA Testing Practices in the United States: A Population-Based Study Between 2000 and 2019

Mehmet Hocaoglu¹, Alain Sanchez-Rodriguez², Hannah Langenfeld³, Cynthia Crowson⁴ and Ali Duarte-Garcia⁵, ¹University of Maryland Medical Center, Midtown Campus, Baltimore, MD, ²Division of Rheumatology, Mayo Clinic, Rochester, MN, ³Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, ⁴Mayo Clinic, Eyota, MN, ⁵Mayo Clinic, Rochester, MN

Background/Purpose: Inappropriate laboratory testing accounts for an important part of avoidable healthcare costs. Anti-nuclear antibody (ANA) is a commonly used laboratory test in rheumatology with a role in the diagnosis of several autoimmune diseases. There is limited data regarding the utilization and frequency of ANA testing. We aimed to perform a population-based study to describe the trends of ANA testing in the United States (US) between 2000 and 2019.

Methods: All patients that underwent an ANA test between 2000 and 2019 in a 27-county region in the American Upper Midwest were identified. Patients with a history of systemic autoimmune disease before testing were excluded. Age and sex-specific incidence rates of ANA testing were adjusted to the 2010 US population. 95% confidence intervals were calculated assuming that the data follows a Poisson distribution. Secular trends in ANA testing were examined using Poisson regression methods.

Results: 72,795 unique individuals underwent 134,098 ANA tests between 2000 and 2019 in our geographic area. The mean age was 50.9 (SD 19.22) years, 65% were female. 96% of the performed tests were through the ELISA method. 46% of the total tests were repeat tests. The mean time between repeated tests was 2.7 years. The cumulative incidence was 12 per 100 person-years (95% CI 11.98, 12.1) for females and 6.43 per 100 person-years (95% CI 6.3, 6.5) for males. There was no significant secular trend in the incidence of ANA testing between 2002 and 2019.

Conclusion: There was a high volume of ANA testing in this US population. Over the study period, 12% of females and 6% of males in population were tested for ANA at least once. This is vastly disproportionate to the reported prevalence of connective tissue disorders from the same region. Repeat testing was common despite its low value. Increased awareness of evidence-based criteria for ANA testing could lead to significant healthcare cost savings and avoidance of potential patient harm.
Table 1. Demographics and testing characteristics of antinuclear antibody (ANA) tested patient cohort between 2000 and 2018

Table 2. Cumulative incidence of ANA testing across age groups in 2002 to 2018 period

Figure 1. Incidence trends of ANA testing in the 2002 to 2018 period
Disclosures: M. Hocaoglu, None; A. Sanchez-Rodriguez, None; H. Langenfeld, None; C. Crowson, None; A. Duarte-Garcia, None.