The effect of cost display and cost charge on laboratory test requests

Abstract Objectives To elucidate the long-term effect of introducing cost display and cost charge on the ordering pattern of a selection of clinical chemistry laboratory analyses. Study Design The study had a retrospective interrupted time-series design. Methods Laboratory tests were selected based on order frequency, medical issues, and test cost. The number of ordered laboratory tests was obtained from the Department of Analytical Support, Region Kronoberg, and was adjusted for the number of visits to a physician. The change in the number of laboratory tests was analyzed using Poisson regression, allowing interaction terms between time and cost display/charge to find rate changes. Four models were constructed, and the best model to fit the data was selected using BIC (Bayesian information criterion). The study period started in January 2010 and ended in December 2018. The pre-intervention baseline time frame ended in August 2013. The first intervention, cost display, was introduced for both secondary and primary healthcare in September 2013, and the second intervention, cost charge, was introduced for primary healthcare in January 2014. Results We demonstrated that the long-term effect of cost display in secondary health care is heterogeneous and that cost charge reduces test ordering, mainly for expensive tests and predominantly in primary healthcare. Conclusions Cost display and cost charge can be implemented to partly reduce clinical chemistry laboratory testing both in the short- and long-term perspective. However, the effect is heterogeneous and depends on the test cost and health care tiers.