A Free T3 Does Not Mean It’s “Free”

Home / Physicians News / A Free T3 Does Not Mean It’s “Free”

A Free T3 Does Not Mean It’s “Free”


Clinical stewardship is about using our health care resources in a responsible manner while providing the best care for our patients.

Thyroid hormone testing has been indicated by Choosing Wisely Canada as an area for improvement. In fact, it is their third recommendation under Endocrinology and Metabolism:

“Don’t use Free T4 or T3 to screen for hypothyroidism or to monitor and adjust levothyroxine (T4) dose in patients with known primary hypothyroidism.”

“T4 is converted into T3 at the cellular level in virtually all organs. Intracellular T3 levels regulate pituitary secretion and blood levels of TSH, as well as the effects of thyroid hormone in multiple organs. Therefore, in most people a normal TSH indicates either normal endogenous thyroid function or an adequate T4 replacement dose. TSH only becomes unreliable in patients with suspected or known pituitary or hypothalamic disease when TSH cannot respond physiologically to altered levels of T4 or T3.”

Source: https://choosingwiselycanada.org/endocrinology-and-metabolism/

Dr. Jeremy Fitzgerald, Section Head of the Division of Endocrinology, recommends that instead of Free T3 and Free T4, physicians should use the TSH test to screen for hypothyroidism, which is an accurate and more cost effective test in these patients.

He also recommends that all physicians take advantage of the tool kit available on the website: Less is More with T3 & T4. By informing physicians about appropriate use of these tests, millions of dollars could be re-deployed from unnecessary health care expenditures. We will reach out directly to physicians that have been identified as high users of these tests to further understand their rationale for using these tests and to discuss the evidence for best practice.

So how are we in RQHR doing? In collaboration with Dr. Fitzgerald, the Clinical Stewardship team has reviewed the 2016 Free T3 and Free T4 orders from the Regina Qu’Appelle Health Region Laboratory Services. Figure 1 indicates the number of each test attributed to individual physicians. Physicians are grouped into categories, depending on the number of annual tests ordered. For Free T3 Eleven (11) high users (i.e., those ordering more tests than would be expected) were determined for Free T3 tests to be anyone ordering >50 tests (~1.2% of physicians).

For Free T4 tests, forty-four (44) were identified to have ordered >200 tests (~7.5% of physicians). Expenditures for Free T3 and Free T4 tests combined amount to more than $300,000 each year. Even eliminating just the tests over the high use thresholds (i.e., 366 Free T3 tests and 13,131 Free T4 tests) would save over $94,400 for the health care system.

Figure 1 – Number of Free T3/T4 tests ordered by physicians in 2016. Values for each category indicate the number of individual physicians within that category.

Submitted by: Robert Parker, Manager, Antimicrobial and Clinical Stewardship Program