Biochemical Stratification of Patient Studies and Findings (16,12,13)

Free T3 (2–7 pmol/L*)Free T4 (12–30 pmol/L*)Thyroid-stimulating hormone (0.45–4.5 μIU/mL*)Biochemical status99mTc uptake (%)Comment on uptake reference range
HighHighLowHyperthyroidism>4.50% FN rate
NormalNormalLowSubclinical hyperthyroidism<4.5 including <0.45 or absent0% TP, comprised FN or FP hypothyroidism
HighNormalLowT3 toxicosis>4.5 or <0.45FP hypothyroidism
NormalHighLowThyroiditisNo cases
LowLowLowSecondary hypothyroidismNo cases
NormalNormalHighSubclinical hypothyroidism>0.45 but <4.5100% FN
Low or normalLowHighPrimary hypothyroidism>0.45 and in over 50% of cases >4.5100% FN
NormalNormalNormalEuthyroid<4.5%9% FP rate (6% hyperthyroid, 3% hypothyroid)
  • * Reference range.