The Free T4 test measures the level of free thyroxine (T4) in your blood, which is an essential hormone produced by the thyroid gland. This hormone helps regulate various bodily functions, including metabolism, energy production, and overall hormonal balance. Unlike total T4, the Free T4 test assesses the unbound form of the hormone, giving a clearer picture of your thyroid function. Abnormal Free T4 levels can indicate conditions such as hypothyroidism or hyperthyroidism, leading to symptoms like fatigue, weight gain, or anxiety. This straightforward test is a crucial step in evaluating thyroid health.