Thyroid Panel (TSH, Total T4, Free T4, Free T3)
Thyroid gland disorders are among the most common hormone conditions seen by doctors. The Thyroid Panel can tell whether or not you have enough thyroid hormone. When thyroid hormones are low, it’s called hypothyroidism.
Symptoms associated with hypothyroidism include, depression, difficulty in losing weight, dry skin, fatigue, headaches, menstrual problems, recurrent infections and cold sensitivity and weight gain.
When the thyroid gland produces too much thyroid hormone, it’s called hyperthyroidism. Symptoms associated hyperthyroidism are agitation, anxiety, difficulty sleeping, excessive sweating, fatigue, increased bowel movements, heat intolerance, nervousness, strong, rapid or irregular heart beat, tremors, weakness and weight loss.
- Thyroid stimulating hormone (TSH)
- Total T4
- Free T4
- Free T3
Methodology: Immunoassay (IA)
Water: Drink plenty of water to stay well hydrated.
Medications: Take all medications as prescribed.
Dietary supplements: Avoid dietary supplements before taking this test.
2-3 business days
Result turnaround times are estimates and not guaranteed. Due to factors outside of our control, such as weather, holidays, confirmation/repeat testing or equipment maintenance, our lab may require additional time to complete tests.
TSH is produced by the anterior pituitary gland in the brain. TSH travels to the thyroid gland at the base of the neck (just below your Adam’s apple) where it stimulates the thyroid gland to produce more thyroid hormones.
The thyroid hormones produced by the thyroid gland are triiodothyronine (T3) and thyroxine (T4). About 80% of the body’s thyroid hormone is T4 and 20% is T3.
T4 is inactive. Cells throughout the body convert inactive T4 into active T3. The thyroid panel can tell you if your body is producing a healthy amount of TSH, and whether your T4 and T3 levels are.
Hormones are transported throughout the body on carrier proteins. T4 is reported as Total and Free T4 to provide an understanding of how much of the total T4 present is available for conversion to T3. The T3 hormone is reported as Free T3 because Free T3 is the form of T3 available to cells to use.
Top Reasons to Test Your Thyroid, by Dr. John Neustadt
Hypothyroidism (Mayo Clinic)
Hyperthyroidism (Mayo Clinic)
Gaitonde DY, Rowley KD, Sweeney LB. Hypothyroidism: an update. Am Fam Physician. 2012;86(3):244-251.
LeFevre ML, Force USPSTF. Screening for thyroid dysfunction: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;162(9):641-650.