Variation in Thyroid Function Tests in Patients with Stable Untreated Subclinical Hypothyroidism

Abstract

Percent variation in TSH was lower in SCH than in euthyroid controls, but increased with higher mean TSH. The number of tests needed to establish disease set points was high. The difference required between two tests to be truly different was 40% for TSH and 15% for fT4 and fT3.