A TSH high-sensitivity blood test is used to check the level of TSH, or thyroid-stimulating hormone, in the blood in order to diagnose or monitor problems with the thyroid gland, states WebMD. It is classified as high sensitivity because it detects the hormone levels with more precision than a standard test.
TSH, also known as thyrotropin, is produced by the pituitary gland, and it helps the body regulate thyroid hormone levels, according to Lab Tests Online.
High TSH levels can indicate hypothyroidism, which means the body is not producing enough thyroid hormones, according to WebMD. Likewise, it also can indicate that a person who is taking thyroid medication is not receiving a sufficient dosage. Least commonly, a high TSH level can indicate a tumor that is causing the pituitary gland to produce too much TSH.
Conversely, low TSH levels indicate that a patient may have an overactive thyroid, according to Lab Tests Online. Hyperthyroidism can be caused by a disease such as Graves Disease, a goiter or a benign tumor. Low TSH levels can be brought on by taking too much thyroid medication. TSH levels can also be affected due to systemic illness, pregnancy, certain medications such as estrogen replacement therapy, and liver problems.