The effect of laboratory requisition modification, audit and feedback with academic detailing or both on utilization of blood urea testing in family practice in Newfoundland, Canada

•Blood urea is not routinely necessary with serum creatinine.•Removing urea from a laboratory requisition was associated with a halving of urea orders.•A process of audit and feedback to family doctors on urea test ordering further reduced urea ordering.•Academic detailing with family doctors following the above measures did not further reduce urea orders significantly. Measuring blood urea at the same time as serum creatinine in stable ambulatory patients in family practice is largely unnecessary. The objective was to assess the relative impact of changing the laboratory requisition versus audit and feedback and academic detailing on the volume of orders for blood urea. A natural experiment was observed over the period April 2015 to March 2018 in the Canadian province of Newfoundland where three health regions had different approaches to trying to reduce such urea testing. The Eastern and Western regions removed urea from the standard laboratory requisition but the test could still be ordered by writing it on the requisition. Central region requisitions continued to list urea. Audit and feedback was undertaken with family doctors in Eastern region after the requisition change and that was followed by academic detailing. A nephrologist gave presentations to groups of family doctors on one occasion in Central region. The volume of serum creatinine testing was largely unchanged over time in each region. The volume of urea testing reduced by 73%, 48% and 28% in Eastern, Western and central regions. Interrupted time series analysis showed significant changes in test volume after requisition change in Eastern and Western regions as well as after audit and feedback in Eastern and the presentations in Central region. The incremental impact of academic detailing was not statistically significant. We conclude that removing urea from standard test order menus was the most effective in reducing test volumes, but combination with audit and feedback augmented the impact.