The most common cause for high thyroid hormone levels is hyperthyroidism, a condition where the thyroid gland releases too much hormone [ 2 ]. The most common causes of hyperthyroidism include [ 32 ]:.
What happens if T3 uptake results are abnormal? By itself, abnormal T3 uptake does not generally cause any symptoms. Instead, any symptoms will be from an underlying cause, such as thyroid dysfunction or problems with TBG levels [ 2 ]. Additionally, an abnormal T3 uptake may or may not indicate a thyroid disorder.
A total T4 test must also be performed to calculate the free T4 index. Once the free T4 index is known, your doctor can determine if there is possible hypothyroidism or hyperthyroidism [ 2 ]. The T3 uptake test indirectly measures the amount of TBG that is bound to thyroid hormones. This test, in combination with a total T4 test, can help identify thyroid dysfunction.
However, this test has been made obsolete by newer types of tests. Low Thyroid Hormone Levels Hypothyroidism. High Thyroid Hormones Levels Hyperthyroidism. Joe Cohen won the genetic lottery of bad genes. As a kid, he suffered from inflammation, brain fog, fatigue, digestive problems, anxiety, depression, and other issues that were poorly understood in both conventional and alternative medicine. All of our content is written by scientists and people with a strong science background.
You have two main thyroid hormones, called T3 and T4. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes. You don't need any special preparations for a T3 blood test. Your health care provider will let you know if you need to stop taking any medicines before your test. Certain medicines can raise or lower T3 levels. There is very little risk to having a blood test.
You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. If your results show high total T3 levels or high free T3 levels, it may mean you have hyperthyroidism. Low T3 levels may mean you have hypothyroidism , a condition in which your body doesn't make enough thyroid hormone.
T3 test results are often compared with T4 and TSH test results to help diagnose thyroid disease. Learn more about laboratory tests, reference ranges, and understanding results. T3 has 2 forms: bound and free. Bound T3 is attached to a protein and free T3 is not attached to anything. The free T-3 test measures only the amount of free T3. The total T3 test measures both free and bound T3 in your blood.
Eye irritation or bulging eyes these are symptoms of Graves' disease, a common cause of hyperthyroidism. Have pernicious anemia, a type of anemia caused when your body can't absorb vitamin B You may also need this test if you have symptoms of hypothyroidism.
This is when the thyroid gland does not make enough thyroid hormones. Symptoms include:. Test results may vary depending on your age, gender, health history, the method used for the test, and other things.
Your test results may not mean you have a problem. It is usually slightly elevated during pregnancy because of increased levels of TBG. T3 is metabolically a more active form of thyroid hormone than T4, but its' effects are of shorter duration. This is a measure of the unbound throxine binding globulins in the blood unsaturated with thyroid hormone.
The less thyroid hormone that is present, the more unsaturated TBG is present. This is an indirect measure of thyroid hormone levels. It has nothing to do with T3, despite the name.
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