Endocrine Disorders: Evaluation and Management

  • Author: Todd T. Brown, MD (More Info)
  • Editors in Chief: Daniel R. Kuritzkes, MD; Joseph J. Eron, Jr., MD
  • Last Reviewed: 11/14/16 (What's New)


  • In patients with a low thyrotropin (TSH), T3 should be measured to evaluate for isolated T3 elevation (T3 toxicosis), determine the severity of thyroid disease, or monitor response to antithyroid therapy
  • In patients with elevated thyrotropin, T3 concentrations are less likely to be low in mild hypothyroidism (Management Guidelines)[Thyroid Lab Guidelines]
  • Most T3 is also protein bound, although newer assays give a more direct measurement of the free fraction T3

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