What tests are used to detect a problem with the thyroid?
The first test your doctor will usually order to detect a problem with your thyroid gland is a TSH test. If your TSH level is abnormal, the doctor will usually then request a free T4 test to confirm the diagnosis. A free T3 test may be requested as well.
- TSH – to test for hypothyroidism and hyperthyroidism, to screen newborns for hypothyroidism, and to monitor treatment with thyroid hormone tablets.
- Free T4 – to test for hypothyroidism and hyperthyroidism.
- Free T3 – to test for hyperthyroidism.
When are these tests ordered?
Because one out of every 4,000 infants is born without a working thyroid gland, there is a national programme in Australia to screen all newborn babies for hypothyroidism with a TSH test on a drop of blood taken from a heel prick.
Otherwise, these tests are requested when your doctor notices that your symptoms resemble those of a thyroid condition. For instance, signs of hypothyroidism include fatigue, weight gain, increased sensitivity to cold, and skin dryness. Signs of hyperthyroidism include fatigue, weight loss, increased sensitivity to heat, and nervousness. Tests are also requested in individuals who have a family history of thyroid disorders.