3 Major Problems With Thyroid Testing

problems thyroid testing

Its estimated that a total of 20 million Americans have a thyroid disorder, but 60% of those people are not diagnosed.

Every cell in the human body needs thyroid hormone to function properly. It effects every system of the body and helps control metabolism.  Proper testing is sorely needed.

Unfortunately there are three major problems with modern testing conventions. The normal ranges are inaccurate, testing is incomplete, and antibody tests are rarely administered.

Normal TSH Range

TSH is an abbreviation for thyroid stimulating hormone. It is released by the pituitary gland in response to the levels of thyroid hormones in the body. Increased TSH tells the thyroid gland to increase hormone production.

Most TSH ranges are way too broad. The original range was made in 1973 by testing a group of 200 people and making a bell curve. Those in the tall portion of the bell curve are considered “normal”. The problem is in this group of people they did not exclude those diagnosed hypothyroid or those who may have it and be undiagnosed. This makes the resulting range inaccurate.

The range they came up with was around 0.5-5.0 mU/L (milliunits per liter). In 2002 the American Association of Clinical Endocrinologists updated it to 0.3-3.0 mU/L. Some places have adopted the new standard, but others have not. Different places use different ranges causing much confusion.

Some studies found a range of 0.5-2.5 was normal in healthy adults.  The TSH normal range needs to reflect the true normal and needs to be standardized.

 

 

Incomplete Hormone Testing

If you walk in to your doctor’s office and ask them to test your thyroid, they will most likely just test your TSH. TSH goes up in response to low thyroid hormone levels to tell your gland to make more thyroid. So high levels means that your thyroid is low.  This does make sense, however that is only part of what is going on.

The thyroid gland makes a hormone called T4. This is the inactive form of the thyroid hormone. The liver then converts T4 to T3 which can be used in the cells. If you have trouble with the conversion you could be hypothyroid with high normal TSH levels. In these cases you have enough thyroid, but your body can’t use it.

Another level of complexity is total versus free T3 tests. Total T3 is exactly what it sounds like, the total amount of thyroid hormones in the body. In order to be transported through the body it has to be attached to a carrier protein. Free T3 is the amount not attached to one of these proteins. The hormone then has to separate from the protein to cross the cell membrane and be used.

Think of the carrier protein as a car. You get in your car and drive to work. You need to get out of your car to walk through the door. You can’t fit your car through the door. If the hormone fails to separate it can’t go to work. Normal total T3 levels but low Free T3 causes hypothyroidism because the hormone is not available inside the cell.

In order to get the big picture all of the above tests need to be done. TSH is only one component of a very complex system.

 

Antibody Testing

Two thyroid diseases are caused by autoimmune disease. Hashimoto’s thyroiditis is hypothyroidism caused by the immune system attacking the thyroid gland. It is the most prevalent cause of hypothyroidism in the industrialized countries. Similarly Graves disease is the leading cause of hyperthyroidism. It causes an antibody to be made that mimics TSH.

Hashimoto’s is diagnosed by testing for thyroid peroxidase (TPO) and antithyroglobulin antibodies (TG).  Testing for Graves disease checks for thyroid stimulating immunoglobulin (TSI).

Unfortunately, despite their prevalence, the tests for these diseases are rarely done.

 

Many people are going to their doctor complaining of thyroid disease symptoms and being told they are fine. I was one of them, until I was finally diagnosed with Hashimoto’s myself. If you suspect your thyroid may be the root of your problems, talk to your doctor about these tests. If they don’t listen, find someone who will.

I am not a medical professional and cannot give medical advice. Find a naturopath or holistic doctor who will help you look at your big picture.

 

Further reading

http://press.endocrine.org/doi/abs/10.1210/jc.2005-0455

http://thyroid.about.com/cs/testsforthyroid/a/newrange.htm

http://www.stopthethyroidmadness.com/tsh-why-its-useless/

http://www.thyroid.org/media-main/about-hypothyroidism/