Thyroid (TSH, Free T4 and FT3)
TSH, Free T4 and FT3 (free T3) are measured in this test (even if your TSH is good).
You are tired ... Ideally, you would like to lie in bed and sleep. Your body feels stiff and rigid and moving hurts. Your mood is depressed or changes rapidly. You feel agitated and sleep poorly.
Most thyroid abnormalities result in too little or too much thyroid hormone being made. This leads to many physical symptoms. With an overactive thyroid, these include: rapid heartbeat, weight loss, nervousness, shaky hands, irritated eyes, sleep problems and feeling agitated. In women, an irregular menstrual cycle may also occur. With thyroid hormone deficiency, patients suffer from weight gain, dry skin, constipation, feeling cold easily, fatigue and, in women, heavy menstrual bleeding.
TSH is made in the pituitary gland, an important hormone-producing gland in the brain. TSH ensures that the right amount of thyroid hormone (T4 and T3) is always produced. Thyroid hormone regulates the use of energy in the body; it has a kind of thermostat function.
Free T4 (FT4, free T4, free thyroxine) is a thyroid hormone. This hormone ensures that all kinds of processes in the body run fast enough. Too low a level indicates a thyroid gland that is working too slowly. Too high a FT4 indicates a thyroid gland that works too fast.
FT3 is the hormone created from T4 that causes the final effect of thyroid hormone. So actually FT3 is more important than T4, but we measure T4 to examine changes in thyroid function.
