Frequency of repeat antinuclear antibody testing in Ontario: a population-based descriptive study

Area of Science:

• Clinical Immunology
• Laboratory Medicine
• Rheumatology

Background:

• Repeat antinuclear antibody (ANA) testing raises concerns regarding necessity, potential patient harm, and healthcare costs.
• Understanding the patterns and drivers of repeat ANA testing is crucial for optimizing diagnostic strategies.

Purpose of the Study:

• To determine the frequency and identify correlates of repeat antinuclear antibody (ANA) testing in Ontario.
• To differentiate between overall repeat testing and repeat testing within a 1-year timeframe.

Main Methods:

• A retrospective descriptive study analyzed ANA tests performed between 2008 and 2015 in Ontario.
• Data from the Ontario Laboratories Information System were used to identify repeat tests and analyze patient and physician characteristics.
• Logistic regression models with generalized estimating equations were employed to assess correlates of repeat testing.

Main Results:

• Over 587,000 ANA tests were analyzed, with 28.1% identified as repeat tests.
• Nearly half of repeat ANA tests (49.9%) were conducted within 12 months of the prior test.
• Rheumatologists were more likely to order repeat ANA tests within 12 months compared to other physicians (36.1% vs. 11.3%).
• Testing in patients with suspected or confirmed connective tissue disease was a significant correlate of potentially redundant testing.

Conclusions:

• A substantial proportion of antinuclear antibody (ANA) tests in Ontario are repeats, indicating potential overuse.
• Rheumatologists are key drivers of repeat ANA testing, suggesting a focus for quality improvement initiatives.
• Findings can inform strategies to enhance the appropriateness and efficiency of ANA testing in clinical practice.