MON-600 Reducing Inappropriate Serum T3 Laboratory Ordering in Patients with Treated Hypothyroidism

Background: Choosing Wisely is a campaign of the American Board of Internal Medicine that aims to promote evidence-based practices to reduce unnecessary ordering of tests or procedures. As part of this campaign, national organizations including the Endocrine Society have identified common tests or procedures that providers should be aware of in their practices. The Endocrine Society advises, “Don’t order a total or free T3 level when assessing levothyroxine (T4) dosing in hypothyroid patients.” This is in line with the co-sponsored American Thyroid Association and American Association of Clinical Endocrinologists clinical practice guidelines for hypothyroidism in adults, which states there is “limited utility” in measuring serum T3 in patients with hypothyroidism, due to typically normal T3 levels (resulting from stimulation of thyroid hormone synthesis by increased TSH) and up-regulation of type 2 iodothyronine deiodinase in these patients. Methods: This study assessed the ordering practices among providers who manage patients with hypothyroidism within our institution, a large urban tertiary/quaternary care academic health system. A best practice advisory (BPA) alert was developed following the collection of baseline data. This BPA consisted of a pop-up window triggered when any type of T3 laboratory test (total and/or free levels) was ordered among patients who have thyroid hormone (both generic and brand-name levothyroxine formulations) listed in the medical record. The BPA alert required user acknowledgement and a clinical decision-making process before the T3 laboratory test order could be placed. Results: Prior to launching the BPA, silent mode testing showed that T3 laboratory tests were inappropriately ordered a mean of 165.8 times per week (standard deviation 17.0). After the BPA alert was actively launched in Sept 2018, inappropriate T3 ordering was triggered a mean of 127.3 times (standard deviation 25.0) in the initial three weeks, dropping to a mean of 115.0 (standard deviation 13.5) in the next three week time period. As a result of the BPA, providers canceled 4.9-12.3% of triggered T3 orders during the six weeks after the BPA launch. The BPA alert currently remains active at our institution. Conclusions: Although national guidelines recommend against ordering serum T3 concentrations during the monitoring of patients with hypothyroidism managed on thyroid hormone replacement therapy, these laboratory tests are inappropriately ordered in many patients. Development of a triggered alert may reduce inappropriate monitoring practices for this common clinical condition, decrease costs, and improve utilization of limited healthcare resources.