Profile Includes:
Thyroid Stimulating Hormone (TSH)
Free thyroxine index (FTI)
T3 uptake (THBR)
Thyroxine (T4)
Thyroid antibody testing is primarily ordered to help diagnose an autoimmune thyroid disease and to separate it from other forms of . It may be ordered to help investigate the cause of a goiter and/or performed as a follow-up when other thyroid test results (such as T3, T4, and/or TSH) show signs of thyroid dysfunction.
One or more thyroid antibody tests may also be ordered if a person with a known non-thyroid-related autoimmune condition, such as systemic lupus erythematosus, rheumatoid arthritis, or pernicious anemia, develops symptoms that suggest thyroid involvement. This involvement may occur at any time during the course of the other condition(s).
If a pregnant woman has a known autoimmune thyroid disease (such as Hashimoto’s thyroiditis or Graves’ disease) or has another autoimmune disorder and thyroid involvement is suspected, then one or more of the thyroid antibodies may be ordered early in the pregnancy and then again near the end. These tests are used to help the doctor determine whether the baby may be at risk of thyroid dysfunction since thyroid antibodies can cross the placenta and cause hypothyroidism or hyperthyroidism in the fetus or newborn.
Thyroid antibody testing may also be ordered when a patient with another autoimmune disorder has symptoms of thyroid dysfunction and/or when she has reproductive difficulties that the doctor suspects may be associated with autoantibodies.
TSH (Thyroid Stimulating hormone) is produced by the pituitary gland. It stimulates the production and release of T4 and T3 by the thyroid gland.
When TSH concentrations are high, the thyroid will make and release excessive amounts of T4 and T3 and the patient may experience hyperthyroidism, with symptoms such as rapid heart rate, weight loss, nervousness, hand tremors, irritated eyes, and difficulty sleeping.
With decreased production of thyroid hormones (hypothyroidism), the patient can experience symptoms such as weight gain, dry skin, constipation, cold intolerance, and fatigue.
Abnormal findings for TSH
If after a TSH test result is high and a T4 test result normal, T3 test result is normal, it can indicate a mild form of hypothyroidism.
If after a TSH test result high and a T4 test result are low, T3 test result is normal or low, it can indicate hypothyroidism.
If after a TSH test result low and a T4 test result normal, T3 test result is normal, it can indicate a mild form of hyperthyroidism.
If after a TSH test result low and a T4 test result normal or high, T3 test result is normal or high, it can indicate hyperthyroidism.
If after a TSH test result low and a T4 test result normal or low, T3 test result is normal or low, it can indicate a nonthyroidal illness, for example a rare pituitary hypothyroidism.