Thyroxine (T4) Test

Thyroxine (T4) Total test measures the total levels (both free and bound forms) of the Thyroxine hormone in the blood. Metabolism is how the human body generates energy. Metabolism or the conversion of food into energy is assessed by the basal metabolism rate (BMR). The thyroid hormones, including T4, have a direct impact on the BMR levels. T4 hormone by the thyroid gland plays a vital role in metabolism, growth and development. The T4 test is used in the diagnosis of clinical as well as subclinical thyroid disorders. The thyroid gland is a type of endocrine gland at the lower front part of the neck. It regulates several bodily functions, including metabolism, energy production and mood. The thyroid gland produces T3 and T4 under the effect of thyroid-stimulating hormone. T3 and T4 hormones are produced by the thyroid gland using iodine obtained from meals. T3 and T4 are present in the blood in bound and free form. Blood tests that are part of a T4 test report are Total T4 and Free T4. Total T4 measures the total amount of tetraiodothyronine in the blood. This T4 test report includes the amount of T4 bound to blood proteins. These proteins help in the transport of the hormone Free T4. Free T4 test report measures the thyroxine that is not bound to proteins. Free T4 is the portion of T4 that is available to other body cells for functioning. If the symptoms point to a thyroid problem, the doctor may prescribe a T4 test. Hyperthyroidism is a condition in which the thyroid is more active. Hyperactive thyroid causes weight loss, a rapid heart rate and increased perspiration. Hypothyroidism is a condition characterised by an underactive thyroid gland. It can result in weight gain, weariness and a feeling of being cold and can cause medical complications if left untreated. The proper diagnosis and timely treatment are essential to avoid complications in thyroid disorders. Thyroid diseases are endemic in certain parts of India where there is a lack of naturally available iodine. Goitre or hyperthyroidism can develop due to a lack of iodine in the diet. T3 and T4 are frequent deficits in the sub-Himalayan region. It is a crucial test to have during and before pregnancy since poor thyroid function might impact the growth of the foetus.