What is Thyroid Function Test?
Thyroid function tests (TFTs) is a collective term for blood tests used to check the function of the thyroid.
Purpose of Test
TFTs is done if a patient is thought to suffer from hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid), or to monitor the effectiveness of either thyroid-suppression or hormone replacement therapy. It is also requested routinely in conditions linked to thyroid disease, such as atrial fibrillation and anxiety disorder.
Test of Result Interpretation
Thyroid-stimulating hormone (TSH, thyrotropin) is generally elevated in hypothyroidism and decreased in hyperthyroidism.
Total thyroxine (Total T4) is generally elevated in hyperthyroidism and decreased in hypothyroidism. It is usually slightly elevated in pregnancy secondary to increased levels of thyroid binding globulin (TBG).
Free thyroxine (Free T4) is generally elevated in hyperthyroidism and decreased in hypothyroidism.
No preparation required.