TSH (thyroid stimulating hormone) is the most common test used to evaluate thyroid function and symptoms related to a thyroid disorder such as hyperthyroidism, or hypothyroidism. Produced by the pituitary gland, the primary role of TSH in the body is to stabilize amounts of T4 (thyroxine) and T3 (triiodothyronine) in the blood. This process controls how much energy the body burns.
The TSH test is often ordered to:
The TSH test is often ordered with a free T4 test, free T3 test, and/or thyroid antibodies. These tests can be ordered together in a panel called a thyroid panel.
Symptoms related to hyperthyroidism include anxiety, weight loss, shaking, weakness, sensitivity to light, or eye problems (swollen eyes, irritation/dryness).
Symptoms related to hypothyroidism include swollen skin, tiredness/fatigue, hair loss, weight gain, dry skin, or irregularity with menstruation in women.
Individuals who are being treated for a thyroid disorder often have the TSH test ordered at regular intervals. It is also ordered when an individual has an adjustment in their thyroid medication. The American Thyroid Association recommends that patients wait 6-8 weeks after adjusting medication before they retest thyroid stimulating hormone levels.
This test is used when Free T4 may be indicated when TBG (thyroxine-binding globulin) problems are suspected. It can also be used to diagnose thyroid disease and screen for hypothyroidism in newborns.
Patient Preparation: Discontinue any supplements containing Biotin for 72 hours prior to specimen collection.