The Thyroid Function Test (TFT) is a group of blood tests used to evaluate how well the thyroid gland is functioning. The thyroid gland produces hormones that regulate metabolism, body temperature, heart rate, and overall energy balance. This test typically measures Thyroid Stimulating Hormone (TSH), Triiodothyronine (T3), and Thyroxine (T4), which together provide a comprehensive picture of thyroid health.

This test is recommended when symptoms of thyroid imbalance are present, such as unexplained weight gain or loss, fatigue, hair thinning, heat or cold intolerance, irregular heartbeat, or menstrual irregularities. It is also used to diagnose conditions like hypothyroidism, hyperthyroidism, thyroiditis, and to monitor patients already on thyroid medication.

Abnormal TSH with altered T3 and T4 levels helps determine whether the thyroid is underactive or overactive. Elevated TSH with low T3/T4 suggests hypothyroidism, while suppressed TSH with high T3/T4 indicates hyperthyroidism. Results must always be interpreted in correlation with symptoms and clinical history.

Test Procedure and Preparation

A blood sample is collected from a vein in the arm. Fasting is usually not required unless advised by the doctor. Certain medications may affect results and should be disclosed prior to testing.

FAQs

Is this test lifelong for thyroid patients? – Often yes

Can stress affect thyroid levels? – Indirectly

Is fasting mandatory? – Usually no

Can pregnancy alter results? – Yes

Are thyroid disorders treatable? – Yes