Optimal thyrotropin level: normal ranges and reference intervals are not equivalent

Abstract

This paper marshals arguments in support of a narrower, optimal or true normal range for thyrotropin (TSH) of 0.4 to 2.5 mIU/L, based on clinical results and recent information on the relatively stable and narrow range of values in patients without thyroid disease. The terminology used for TSH results is clarified in an attempt to help physicians interpret, explain, and respond to TSH test results for their patients.