Elisha McCoy

Background Research into low‐value routine testing at children's hospitals has not consistently evaluated changing patterns of testing over time. Objectives To identify changes in routine laboratory testing rates at children's hospitals over ten years and the association with patient outcomes. Design, Settings, and Participants We performed a multi‐center, retrospective cohort study of children aged 0–18 hospitalized with common, lower‐severity diagnoses at 28 children's hospitals in the Pediatric Health Information Systems database. Main Outcomes and Measures We calculated average annual testing rates for complete blood counts, electrolytes, and inflammatory markers between 2010 and 2019 for each hospital. A > 2% average testing rate change per year was defined as clinically meaningful and used to separate hospitals into groups: increasing, decreasing, and unchanged testing rates. Groups were compared for differences in length of stay, cost, and 30‐day readmission or ED revisit, adjusted for demographics and case mix index. Results Our study included 576,572 encounters for common, low‐severity diagnoses. Individual hospital testing rates in each year of the study varied from 0.3 to 1.4 tests per patient day. The average yearly change in hospital‐specific testing rates ranged from ‐6% to +7%. Four hospitals remained in the lowest quartile of testing and two in the highest quartile throughout all ten years of the study. We grouped hospitals with increasing (8), decreasing (n = 5), and unchanged (n = 15) testing rates. No difference was found across subgroups in costs, length of stay, 30‐day ED revisit, or readmission rates. Comparing resource utilization trends over time provides important insights into achievable rates of testing reduction.