How are thyroid function tests used?
TFTs are is used to help diagnose hypo- and hyperthyroidism which can be due to various thyroid diseases. In some laboratories, the initial test for thyroid disorders is a TSH test. If your TSH level is abnormal, it will usually be followed up with a FT4 measurement (or occasionally total T4). In some cases FT3 (or total T3)will also be performed. Often, the laboratory will do this follow-up testing automatically, and this is known as reflex testing. This saves your doctor time from having to wait for the results of the initial test and then requesting the additional testing to confirm or clarify a diagnosis. Follow-up tests are often performed on the original sample that was submitted when the initial test was requested. When is it requested? A thyroid panel may be requested as part of a health check-up or when symptoms suggest hypo- or hyperthyroidism due to a condition affecting the thyroid. Signs and symptoms of hypothyroidism may include weight gain, dry skin, constipation, cold i
