Thyroid Deficiency
My wife has been worried for some time that Ashleigh may have some thyroid issues as a result of her TBI. She had a battery of blood tests but the results came back within the normal range. It was not until months later when she read more about the thyroid tests that we found out that you may need to test for a few other factors to get a more detailed answer. The doctor added the Free T3 and Free T4 tests. Ashleigh did show a problem with the Free T3 and Free T4 tests and has started on a low dose of Armour Thyroid medication. Remember that you know yourself or the TBI survivor in your family best, so if you have a concern be persistent.
I pasted some details below from the About.com page on thyroids. There is a lot more info out there on the Web and from your doctor if you suspect any thyroid issues.
TSH Test
The most common thyroid test is the blood test that measures the amount of thyroid-stimulating hormone (TSH) in your bloodstream. The test is sometimes called the thyrotropin-stimulating hormone test.
TSH that is elevated, or above normal, is considered indicative of hypothyroidism. TSH that is “suppressed” or below normal, is considered evidence of hyperthyroidism.
As of 2003, the American Association of Clinical Endocrinologists is recommending that the normal range run from 0.3 to 3.0, versus the older range of 0.5 to 5.5. So, according to the new standards, levels above 3.0 are evidence of possible hypothyroidism, and levels below 0.3 are evidence of possible hyperthyroidism. Keep in mind that there is disagreement among practitioners, and some follow the older range, others use the newer range.
Free T4 / Free Thyroxine
Free T4 measures the free, unbound thyroxine levels in your bloodstream. Free T4 is typically elevated in hyperthyroidism, and lowered in hypothyroidism.
Free or unbound T4 levels represent the level of hormone available for uptake and use by cells. Bound levels represent a circulating hormone that may not all be immediately available, because it is affected by other drugs, illness, and physical changes such as pregnancy. Because the free levels of T4 represent immediately available hormone, free T4 is thought to better reflect the patient’s hormonal status than total T4 (below).
Total T4/Total Thyroxine/Serum Thyroxine
This test measures the total amount of circulating thyroxine in your blood. Thyroxine, a hormone produced by the thyroid, is also known as T4. A high value can indicate hyperthyroidism, a low value can indicate hypothyroidism. Total T4 levels can be elevated due to pregnancy, and other high estrogen states, including use of estrogen replacement or birth control pills.
Total T3/Total Triiodothyronine
Triiodothyronine is the active thyroid hormone, and is also known as T3. Total T3 is typically elevated in hyperthyroidism, and lowered in hypothyroidism.
Free T3 / Free Triiodothyronine
Free T3 measures the free, unbound levels of triiodothyronine in your bloodstream. Free T3 is considered more accurate than Total T3. Free T3 is typically elevated in hyperthyroidism, and lowered in hypothyroidism.