Thyroid Function Test (TFT)

A Thyroid function test (TFT) commonly refers to the quantitation of thyroid stimulating hormone (TSH) and circulating thyroid hormones in serum to assess the ability of the thyroid gland to produce and regulate thyroid hormone production.

The following are approximate values for what is normal for TSH and thyroxine levels. These are a rough guide only and will vary from hospital to hospital. Normal range for thyroid-stimulating hormone: 0.4-4.0 mU/L. Normal range for thyroxine: 9-24 pmol/L.

At MSK, the normal range is 0.60 milli-international units per liter (mIU/L) to 4.80 mIU/L. If your TSH level is low, you're in a state of hyperthyroidism. This means your thyroid function is too active. If your TSH level is high, you're in a state of hypothyroidism.