Thyroid level tests, including thyroid-stimulating hormone (TSH) and free T4, help diagnose underactive or overactive thyroid. Doctors may also check free T3, calcitonin, thyroglobulin, or thyroid ...

RADIOIODINE (I131) has been used extensively in the diagnosis of thyroid disorders, and many tests have been developed. 1–3 Most of these tests are based on two aspects of thyroid activity: the ...