T3 is too high
T3, a thyroid hormone found to be too high in the blood test, indicates that the organ is overactive. The free form fT3, which is not bound to transport proteins, is usually determined. The cause is usually either a disease of the thyroid gland, which leads to increased hormone production, or a dosage that is too high when taking thyroid hormone tablets.
T4 or thyroxine as a precursor of T3 can also be elevated but may also be in the normal range. The thyroid’s regulatory hormone, TSH, is mostly reduced when T3 levels are too high. The body tries to regulate the further production of thyroid hormones.
T4 is too high
If the T4 is too high with elevated thyroid values, there is usually an overactive thyroid gland. The cause may be a thyroid disease that leads to an increased production of the hormone tetraiodothyronine (T4). Normally, the free, i.e. not bound to transport proteins, form of T4 is measured, which is then called fT4.
Another possible cause of an increase in T4 may be treatment with thyroid hormones. If, as a result, the value is too high, a dosage that is too high may be the cause. If the value of T4 is too high, the control hormone of the thyroid gland TSH is usually too low. In this way the body tries to counter the excessive supply of thyroid hormones. The other thyroid hormone T3 can often also be too high, but it can also be in the normal range.
TSH is too high
If the TSH (Thyroidea= thyroid stimulating hormone) is too high in the thyroid gland values, then the cause is usually an underactive thyroid gland. In many cases, however, this goes unnoticed at first and is only noticed after the blood test. TSH is the control hormone of the thyroid gland and is produced by the pituitary gland.
It stimulates the thyroid gland to produce and release hormones. In the case of hypofunction, the body produces more TSH and can thus maintain hormone production in many cases. This means that the TSH is too high and the thyroid hormones T3 and T4 are in the normal range.
This is why there are usually no symptoms and it is called latent (hidden) hypothyroidism. When an increase in TSH production is no longer sufficient to achieve sufficient thyroid hormone production, the values for T4 and possibly T3 drop. In such a case there is a manifest hypothyroidism.
Symptoms such as listlessness, constipation and brittle hair and nails may occur.The most frequent causes of this functional disorder and thus also the too high TSH are on the one hand iodine deficiency and on the other hand the thyroid gland disease Hashimoto. In extremely rare cases, however, the TSH is also too high in a disease that leads to hyperthyroidism. This is a benign tumor that produces TSH in an uncontrolled manner and thus stimulates the actually healthy thyroid gland to produce excessive amounts of hormones. Typical for this extremely rare disease is therefore a simultaneous increase in TSH and the thyroid hormones T3 and T4.
