Thyroid function tests play a central role to assess thyroid function and are valuable companions for clinicians. The evolution of the tests is permanent and clinical laboratories are key players in defining decision limits and validating new methods. In addition, several standardization efforts are also underway and will have an impact on test performance.

However, thyroid function tests can be sensitive to different types of interference and therefore have an impact on the clinical decision. Such interference may be suspected in the event of clinical and / or biological discrepancies. Their identification is based on additional laboratory tests including a comparison of assay methods, dilution procedures, blocking reagent studies, and polyethylene glycol precipitation. Interdisciplinary exchanges with clinical teams are essential to identify these interferences and continue to improve the performance of our assays.