Thyroid Function Tests- what your results can mean

If you’ve had thyroid function tests and received the results, this easy-to-understand short animation explains what they are measuring and what you are likely to see on the form.
These are blood tests used to check how your thyroid is working. They measure thyroid stimulating hormone or TSH, Thyroxine or T4 and Triiodothyronine or T3
The thyroid gland is found at the base of the neck. It produces thyroid hormones and releases them into the bloodstream. They control your body’s metabolism and regulate things like your heart rate and body temperature. It is important that your thyroid hormones levels are not too high or low and that they are kept in an even balance. If your T4 levels are low you may feel tired or experience weight gain. This is called Hypothyroidism . If your T4 levels are too high everything runs at a faster rate. You may experience heat intolerance or weight loss. This is Hyperthyroidism. There is a feedback mechanism to make sure levels remain stable. The pituitary gland controls T4 levels. WhenT4 levels are too low it releases more TSH. WhenT4 levels are too high it releases less TSH. In the blood sample sent to the lab we measure TSH, Free Thyroxine (FT4) and Free Triiodothyronine (FT3).