Effects of a diagnostic stewardship intervention to de-implement widespread use of a rapid respiratory multiplex PCR...

Rapid respiratory diagnostic tests are widely utilized but often do not change clinical management. We evaluated the effects of an intervention to de-implement widespread use of a multiplex respiratory pathogen PCR panel (RPP) in favor of a selective use strategy. This was a retrospective, quasi-experimental study conducted in a safety-net healthcare system. We compared RPP utilization during 2 years of unrestricted, widespread use (24 July 2022-23 July 2024) and 1 year after implementation of a selective use strategy (24 July 2024-23 July 2025). The primary outcome was change in weekly test volume as assessed by interrupted time-series analysis (ITS). During the widespread and selective use periods, 8,923 and 184 RPPs were performed, respectively. By ITS, test volume declined by 66 per week (P < 0.001) immediately after the intervention; this reduction was sustained over the subsequent year. Median weekly tests decreased from 83 (IQR 67-103) to 3 (IQR 2-5) (P < 0.001), a relative decline of 96.4%. The median age of patients tested decreased from 50 to 7 years (P < 0.001). The proportion of positive tests was similar (32.1% vs 35.9%; P = 0.28); however, the pathogens detected differed. Annualized laboratory costs decreased from $741,446 to $30,623. Use of an influenza/RSV/SARS-CoV-2 PCR decreased from a weekly median of 331 (IQR 189-586) to 118 (IQR 25-390) (P < 0.001). An intervention to de-implement widespread use of an RPP in favor of selective use led to a greater than 95% reduction in tests that was sustained over 1 year.

Use of rapid respiratory multiplex PCR panels (RPPs) is widespread but has not been shown to reduce antibiotic use or improve clinical outcomes. Reducing low-value use of these tests is therefore an important diagnostic stewardship target. To our knowledge, this is the first study describing a successful intervention to de-implement widespread use of this test among pediatric and adult patients and in ambulatory and inpatient care locations in favor of targeted use.