Thyroid Stimulating Hormone and Thyroid Hormones (Triiodothyronine and Thyroxine): An American Thyroid Association-Commissioned Review of Current Clinical and Laboratory Status

Physiological, pathophysiological and pharmacological factors affecting thyroid assays need to be considered in the patient's clinical context for appropriate test ordering and result interpretation.

Routine thyroid assays remain susceptible to idiosyncratic analytical interference that may produce spurious results.

Improved standardization needs to be demonstrated before results from different assays can be considered equivalent.

Mass spectrometry shows promise, but more evidence of clinical utility and improved throughput is required before routine use.

Close clinical-laboratory collaboration is encouraged to avoid pitfalls in thyroid testing and resolve clinically discrepant results.