TSH (Basic Thyroid Testing)
Quest Diagnostics Test Code: 899
A TSH test is commonly ordered to help evaluate a person’s thyroid function and aid in the diagnosis of thyroid disorders such as hyperthyroidism or hypothyroidism. It may also be used in some cases to evaluate pituitary gland function.
Thyroid stimulating hormone (TSH) is a hormone that is produced by the pituitary gland in the brain to stimulate the thyroid gland to produce the hormones triiodothyronine (T3) and thyroxine (T4) that get secreted into the bloodstream. These hormones are responsible for the regulation of energy metabolism in the body. This test is used to evaluate the function of the thyroid and pituitary glands. This test, along with a T4, is typically ordered when a patient has signs and symptoms of hyper or hypothyroidism or another thyroid disorder, like Graves disease.
The thyroid gland regulates all metabolic processes of the body. Every single cell is affected by its hormone. It is located in the middle of the lower neck area. Although the nodes and other changes of the gland should be closely monitored by health professionals, changes in its function are what bothers patients. Most often, the gland on ultrasound examination appears to be healthy, but the lab work reveals increased or decreased amount of its hormone in the bloodstream.
According to American Thyroid Association estimation, 12% of the U.S. population has some kind of thyroid gland disease (problem with its function of morphology). Another frightening fact is that 60% of people with thyroid disease are not aware of the condition.
What does this test reveal about your health?
By testing TSH level, we will determine if the function of the thyroid gland is adequate. TSH and thyroid gland hormones are in direct correlation and (usually) the imbalance of TSH is a sign of an imbalance of thyroid hormones. We say usually because, in the case of the newly diagnosed patient, a complete hormonal profile is needed. In medical terminology, the lack of thyroid hormones is known as hypothyroidism, while the excess amount of these hormones is known as hyperthyroidism.
By testing TSH level, medical practitioner wants to determine if the function of the thyroid gland is adequate. TSH and thyroid gland hormones are in direct correlation and (usually) the imbalance of TSH is a sign of an imbalance of thyroid hormones. In case of thyroid gland hyperfunction, TSH will decrease (or even become undetectable) and in cases of thyroid hypofunction, the TSH level will increase.
Signs and symptoms of hyperthyroidism
• Weight loss
• Increased heart rate
• Difficulty sleeping
Signs and symptoms of hypothyroidism
• Weight gain
• Dry skin
• Cold intolerance
Also Known As: Thyroid-Stimulating Hormone
Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For people on hemodialysis, specimen collection should be delayed for 2 weeks.
Estimated Time Taken
Turnaround time for the TSH test is typically 1 business day.