Reducing unnecessary free thyroid hormone testing by the reinforcement of a reflexive algorithm in an outpatient...

Thyroid dysfunction is one of the most common endocrine disorders. Thyroid function tests, including TSH, Free T4, and Free T3, are essential for diagnosis and patient management. Current guidelines recommend TSH as the first-line test, with additional testing for Free T4 and Free T3 only when TSH is abnormal or in specific clinical scenarios. Despite guideline recommendations, inappropriate ordering of free hormone tests is prevalent, leading to increased healthcare costs, diagnostic inefficiencies, and potential patient burden. In this study, we aimed to assess thyroid function testing utilization in the Saskatoon Health Region and identify opportunities to enhance test appropriateness.

A retrospective analysis of thyroid function test utilization was conducted in the Saskatoon Health Region to identify gaps in guideline adherence. Inappropriate Free T4 and Free T3 testing was defined as tests ordered with TSH results in the laboratory reference range. Interventions were developed, including reinforcing the reflexive testing algorithm in outpatient settings and restricting free hormone testing to pre-approved specialists. Metrics for evaluation included testing volume trends, physician satisfaction, and cost savings.

Pre-intervention analysis revealed significant increases in thyroid function testing volumes from 2016 to 2019: TSH orders increased by 34.5 %, Free T4 by 36.4 %, and Free T3 by 18.8 %. A substantial proportion of tests involved normal TSH ordered in combination with Free T4 and/or Free T3, which is unnecessary. Compared to baseline volumes, post-intervention Free T4 and Free T3 testing volumes decreased by approximately 60 % and 40 %, respectively.

Implementing and reinforcing a reflexive thyroid testing algorithm substantially reduced inappropriate Free T4 and Free T3 testing. Utilization management improved diagnostic efficiency, reduced unnecessary healthcare costs, and minimized patient harm.