|
|
Article: Interpretation of laboratory thyroid function tests for the primary care physician. (Featured CME Topic: Thyroid Dysfunction/Disease).
- Article from:
- Southern Medical Journal
- Article date:
- May 1, 2002
- Author:
CopyrightCOPYRIGHT 2002 Southern Medical Association. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
THYROID FUNCTION TESTS are frequently ordered in both the inpatient and outpatient settings. A basic knowledge of thyroid-hormone physiology is helpful in interpretation of laboratory results.
Thyroxine ([T.sub.4]) is released from the thyroid gland along with small amounts of triiodothyronine ([T.sub.3]) and thyroglobulin under the guidance of thyroid-stimulating hormone (TSH). Secretion of TSH is principally regulated by circulating levels of thyroid hormones (via a negative-feedback loop) and hypothalamic thyrotropin-releasing hormone (TRH). More than 99% of the thyroid hormones are bound to proteins, including thyroid-binding globulin (TBG), thyroxine-binding ...