TSH level	Free T4 level	Free T3 level	Likely diagnosis
High	Low	Low	Primary hypothyroidism
High (>10 μU per mL [10 mU per L])	Normal	Normal	Subclinical hypothyroidism with high risk for future development of overt hypothyroidism
High (6 to 10 μU per mL [6 to 10 mU per L])	Normal	Normal	Subclinical hypothyroidism with low risk for future development of overt hypothyroidism
High	High	Low	Congenital absence of T4-T3–converting enzyme; amiodarone (Cordarone) effect on T4-T3 conversion
High	High	High	Peripheral thyroid hormone resistance
Low	Low	Low	Pituitary thyroid deficiency or recent withdrawal of thyroxine after excessive replacement therapy