A blood sample is the best screening method for any thyroid disorder. A blood analysis will help determine the levels of T4 and T3 that exist in the blood and can provide a picture of how the thyroid is functioning.
If your doctor feels further tests are necessary, they may administer a radioactive iodine uptake test. The type of radioactive iodine used for the test will not harm the thyroid or pose any risk to you. After 24 hours, special equipment is then used to measure the amount of radioactivity over the thyroid gland.
Thyroid tests can often come back normal or sub clinical although the thyroid is not functioning as it should be and all the symptoms of hypothyroidism are experienced. This is because a normal result on tests only indicates that the thyroid functioning falls within the average or slightly below average range.
Because thyroid functioning can vary from person to person, what may be normal for one person is not necessarily so for the next person. That is why the results of thyroid tests must always be seen in the context of symptoms experienced by the patient.
Patients who have a good working knowledge of their bodies can provide valuable information which assists the diagnostic process.