What Thyroid Blood Tests Should Be Done



If you are exhibiting any of the symptoms of thyroid disorders, your doctor will probably want you to have a blood test to determine whether or not a thyroid disorder exists.

Your thyroid gland produces hormones that regulate your body’s metabolism. They are Thyroxine (T4) and Triiodothyroxine (T3). The thyroid gland stores these hormones and releases them when they are needed.

There are three reasons your physician would request a thyroid test for you:
1. Find out what is causing your problem and see if it is an abnormal TSH.
2. Regular check up to see how your thyroid is doing and if the current treatment is working.
3. To check for congenital hypothyroidism in a newborn. If not treated soon, this condition can cause severe problems and intellectual disabilities if they don’t treat it soon after the child is born.

Depending on your symptoms and your doctor’s preferences, one of these three tests will generally be ordered:
• Total Thyroxine (T4)—The majority of the thyroxine in your body’s blood is attached to a protein and called thyroxine-binding globulin. An amount smaller than 1% is unattached or free T4 which affects the tissue function in the body. This test measures both bound and free thyroxine.
• Free Thyroxine (FTI) (FT4)—When free thyroxine is measured directly, it is FT4. If not it is calculated as the free thyroxine index or FTI. The FTI tells the amount of T4 is in the blood compared to the bound T4. It tells if the amounts of T4 are abnormal because of abnormal amounts of thyroxine-binding globulin.
• Triiodothyronine (T3)—The majority of the T3 in your blood is attached to what is known as thyroxine-binding globulin. An amount smaller than 1% of the T3 is unattached. This test measures both bound and free triiodothyronine. The greater effect on the way the body uses energy is by T3, even though T3 is usually in a lesser amount.

It is important that your doctor know any medication both prescription and OTC medications you are taking because many medications can interfere with the results of the test.

There are other tests that can be used to diagnose thyroid dysfunctions. Even though some of these tests are considered controversial, they are well-accepted and regularly used by alternative, holistic, and integrative physicians.
• Iodine Patch Tests—During this test the physician will paint a patch of pure iodine solution on the skin. The patch is watched to determine how quickly it disappears. It measures iodine deficiency and how rapidly your body absorbs the iodine.
• Saliva Testing—This test is beginning to grow in popularity with integrative and complementary practitioners. Several companies claim to provide this test, but the one most used is Diagnos-Techs.
• Urinary Testing—This is not a widely used test, and is rarely performed in the US. It is used mainly by medical professionals in Europe. This test is more expensive than conventional testing.
• Basal Body Temperature Testing—Only a few alternative practitioners use this test as their main method of diagnosis. This test involves taking your temperature early in the morning before any movement. This test says basal temperatures below 97.8 indicate you have low thyroid function. Most conventional medical professionals do not think this test is useful to diagnose thyroid function.
Your doctor may use one or more of these tests to diagnose your thyroid disorder. What is important is to determine exactly what your problem is so you can be on the road to recovery.