A Thyroid Function Test (TFT) is a blood test used to assess how well the thyroid gland is working. It commonly measures TSH (Thyroid-Stimulating Hormone), T3, and T4 levels to help identify thyroid disorders such as hypothyroidism and hyperthyroidism.
Thyroid hormones influence metabolism, energy levels, heart rate, body temperature, and several other important body functions. A thyroid blood test may be recommended when symptoms such as unexplained weight changes, tiredness, irregular heartbeat, mood changes, increased sensitivity to cold or heat, or changes in menstrual cycles are present.
What Does a Thyroid Function Test Measure?
Depending on the test ordered, a TFT may include TSH, Free T3 (FT3), and Free T4 (FT4). These results help healthcare professionals evaluate thyroid hormone balance and determine whether additional assessment may be needed.
Why Is a TFT Test Done?
A TFT test can help evaluate suspected thyroid problems, monitor people already receiving thyroid treatment, and assess changes in thyroid hormone levels. Your doctor may interpret the results alongside your symptoms, medical history, and other investigations.
Preparation and Results
Most thyroid blood tests require a simple blood sample. Fasting is not always necessary, but preparation requirements can vary depending on other tests being performed. Follow your healthcare provider's instructions before testing.