How are thyroid disorders diagnosed?

Dr. Jeanne Morrison, PhD
Family Practitioner

Your doctor may be able to diagnose a thyroid disorder during a physical examination. Several more tests can confirm a thyroid disorders. Blood tests can measure the level of thyroid hormones in your blood to test whether your thyroid is overactive or underactive. An ultrasound or thyroid scan can allow your doctor to see an image of your thyroid, and antibody tests can confirm whether an autoimmune disorder is causing your thyroid disorder.

First, your doctor will ask about your medical history. If you’re having new symptoms, tell your doctor. They’ll also complete a physical examination and blood tests to help reach a diagnosis.

If you have an enlarged thyroid gland, your doctor may decide to send you for an imaging test. That can include a radioactive thyroid scan or an ultrasound of the thyroid. However, it’s not one-size-fits all for everybody—it depends on your symptoms.

A blood test to measure thyroid stimulating hormone (TSH) is the most efficient and sensitive test for hypothyroidism available. TSH is produced by the pituitary gland in response to TRH secretion. An elevated TSH value indicates thyroid failure and a lack of adequate amounts of thyroid hormone to maintain normal body functioning. Conversely, a low TSH value indicates excess production of thyroid hormone. The normal range of serum TSH is 0.5 - 5.0 mU/ml. If the TSH value is abnormal, then evaluation of the serum free- T4 becomes necessary to further evaluate the exact location of the dysfunction (i.e.: at the level of the thyroid, the pituitary, or hypothalamus).

Dr. Jack Merendino, MD

Like almost any medical problem, there are various ways that a thyroid problem can be diagnosed. Blood tests, especially measurement of the TSH (thyroid-stimulating hormone), often diagnose thyroid problems before any symptoms develop. Sometimes a person comes in with clear-cut or suggestive symptoms and a blood test confirms the suspected thyroid problem. Physical exam may reveal an enlarged thyroid gland or the presence of a thyroid nodule and this may be the first indication of a thyroid problem. In this case a thyroid ultrasound as well as blood tests are the appropriate steps in evaluation. The ultrasound may confirm the presence of a nodule or may identify an abnormal “echotexture” or sound-wave appearance of the thyroid tissue may be a clue to a thyroid disorder as well.  

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.