Free Thyroxine T4 Levels. High levels of any of these tests (total t4, free t4, or free t4 index) may indicate an overactive thyroid, also known as hyperthyroidism. Measurement of total t4 gives a reliable reflection of clinical thyroid status in the absence of protein binding abnormalities.
A free t4 level in the optimal range usually indicates normal thyroid gland function. A free t4 level in the normal range is usually accompanied by a tsh level that is also in the normal range. Free and total thyroxine (ft4 and t4) causes low.
In these situations, it is better to ask both for tsh and free t4 for thyroid evaluation, which will typically be in the normal range.
Thyroxine free the most active of t4. The main function of it is to accelerate metabolic processes. A free t4 level in the optimal range usually indicates normal thyroid gland function. The values of t4 and ft4 are regulated by a sophisticated mechanism called hypothalamus pituitary thyroid axis, which allows the body to regulate the production of thyroid hormones.thanks to this system, the hormones ft3 and ft4 are kept in the normal range from tsh (thyroid stimulating hormone or thyrotropin), produced at the pituitary level.