MICROANATOMY

Detailed explanation-1: -A low level of TSH and high levels of T3 and/or T4 usually means you have an overactive thyroid. Doctors may refer to these measurements as “free” T3 and T4 (FT3 and FT4). What’s considered normal varies depending on things such as your age and the exact testing technique used by the laboratory.

Detailed explanation-2: -A TSH level lower than normal indicates there is usually more than enough thyroid hormone in the body and may indicate hyperthyroidism. When hyperthyroidism develops, free thyroxine (T4) and free triiodothyronine (T3) levels rise above normal. Other laboratory studies may help identify the cause of hyperthyroidism.

Detailed explanation-3: -However, in subclinical hyperthyroidism, due to a variety of possible thyroid issues, thyroid hormonal output doesn’t decrease like it normally should in response to the low TSH levels. This leads to low TSH levels and normal thyroxine (T4) and triiodothyronine (T3) levels, resulting in subclinical hyperthyroidism.

Detailed explanation-4: -A low TSH with normal free T4 and T3 levels is consistent with subclinical hyperthyroidism. Some patients with nodular goiter and Graves’ disease, particularly early in the disease course, will have predominant elevations in T3 due to increased conversion of T4 to T3 and a disproportionate increase in T3 secretion.

Detailed explanation-5: -Low TSH levels indicate hyperthyroidism. This is also known as an overactive thyroid. If a person’s thyroid gland is secreting levels of hormones that are too high, the pituitary gland produces less TSH.