Sustainable Laboratory-Driven Method to Decrease Repeat, Same-Day WBC Differentials at a Tertiary Care Center

Abstract

Objectives: A CBC with WBC differential is often ordered when a CBC alone would be sufficient for patient care. Performing unnecessary WBC differentials adds to costs in the laboratory. Our objective was to implement a laboratory middleware algorithm to cancel repeat, same-day WBC differentials to achieve lasting improvements in laboratory resource allocation.

Methods: Repeat same-day WBC differentials were first canceled only on intensive care unit samples; after a successful trial period, the algorithm was applied hospital-wide. We retrospectively reviewed CBC with differential orders from pre- and postimplementation periods to estimate the reduction in WBC differentials and potential cost savings.

Results: The algorithm led to a monthly WBC differential cancellation rate of 5.40% for a total of 10,195 canceled WBC differentials during the cumulative postimplementation period (September 25, 2019, to December 31, 2020). Nearly all (99.94%) differentials remained canceled. Most patients only had one WBC differential canceled (range, 1-38). Savings estimates showed savings of $0.99 CAD per canceled differential and 1,060 minutes (17.7 hours) of technologist time.

Conclusions: A middleware algorithm to cancel repeat, same-day WBC differentials is a simple and sustainable way to achieve lasting improvements in laboratory utilization.

Keywords: CBC with differential; Quality improvement; Test utilization.