Changing Patterns of Routine Laboratory Testing over Time at Children's Hospitals

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 10 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.