Thyroid (TSH/fT3/fT4)

TSH (thyroid-stimulating hormone), fT3 (free triiodothyronine) and fT4 (free thyroxine) form the basic profile of thyroid function. TSH responds most sensitively to disturbances. fT3 is the active hormone — its conversion from fT4 requires selenium, zinc and iron. Hashimoto's thyroiditis (anti-TPO, anti-TG) is looked at via the antibodies and is not part of a routine blood count. Measurable in the OM Vital blood test.

What thyroid hormones do in the body

The pituitary gland releases TSH and thereby stimulates the thyroid to produce mainly T4. In the liver, kidneys, muscles and brain, T4 is converted into the more active T3. T3 acts in almost every cell of the body: it sets the basal metabolic rate, heat production, heart rate, gut movement, fat and cholesterol metabolism and the renewal of skin and hair. When fT4 and fT3 rise, the pituitary reduces TSH release – which is why TSH and the free hormones usually move in opposite directions.

Too little thyroid hormone – what happens in the body?

When fT4 and fT3 fall, metabolism slows down: the body produces less heat (feeling cold), the heart beats more slowly, the gut becomes sluggish (constipation), the skin becomes dry, hair grows more slowly and falls out more, cholesterol rises and more water is retained in the tissues. Drive and concentration decline. TSH usually rises, because the pituitary drives the thyroid harder. A common cause is Hashimoto's thyroiditis.

Too much thyroid hormone – what happens in the body?

When fT4 and fT3 rise, metabolism speeds up: the basal metabolic rate increases (weight loss despite appetite), the body produces more heat (sweating, heat intolerance), the heart beats faster and may become irregular, the gut works faster, the hands tremble, restlessness and sleep problems increase. Over time more bone substance is broken down. TSH is then usually very low. Causes include Graves' disease, thyroid nodules that produce hormone autonomously, or too high a dose of thyroid hormone.

The interpretation is given in your report.