The doctor has a patient he thinks has a malfunctioning thyroid gland. He is not sure about the nature of the problem & would like to obtain information about this patient. What type of diagnostic tool should he use & what sort of information might she obtain about the state of the thyroid?
If the doctor supposes that there exists an abnormal function of thyroid gland, he can prescribe a set of blood tests that verify the levels of hormones produced by thyroid gland. The thyroid gland produces 3 types of hormones such that: triiodothyronine (T3), thyroxine (T4) and hormones that regulates the calcium levels in the body.
Thyroid gland uses iodine to secrete T3 and T4, hence, the hormone triiodothyronine contains 3 atoms of iodine and thyroxine contains 4 atoms of iodine. The hormone T3 is the most active in the body, increasing it's metabolic rate.
The blood tests usually monitor the levels of thyroid-stimulating hormone, TSH, that is secreted by the pituitary gland when the levels of T3 and T4 vary. TSH hormone stimulates the thyroid gland to produce more T3 and T4 hormones.
If the levels of TSH are increased, then the thyroid gland is underactive and the patient has hypothyroidism, while, if the levels of TSH are decreased, then the thyroid gland is overractive and the patient has hyperthyroidism. Usually, the diagnostic of hypothyroidism or hyperthyroidism is finally decided only after performing other set of blood tests that detect the levels of T3 and T4.
If the doctor needs to observe the structure, shape and size of thyroid gland, he can request thyroid scans and uptake tests. The reason a doctor can request these types of tests is to detect inflammation or abnormalities of the gland, or identification of growths, such that lumps or nodules, and identification of their nature.
The thyroid scan test can be performed after a patient either swallow an amount of radioactive iodine, or the patient is injected with radioactive iodine, 24 hours before the test.