Understanding Your Test Results


Making sense of my test results was one of the first things I struggled with. They are much easier to understand once you learn the causes and relationships behind each item being tested. Start by remembering these three things:

  1. Your immune system is mistakenly sending out antibodies (TRAbs) targeted at your thyroid.
  2. Your thyroid responds to this attack by creating and releasing more thyroid hormones (T3 and T4) into your bloodstream, with no “off switch”. This is why Graves disease is classed as a “hyperactive” thyroid.
  3. Your pituitary gland sees the high levels of T3 and T4 in your bloodstream, so it thinks that no TSH is required and shuts down production. This results in less (often none) ‘Thyroid Stimulating Hormone’ (TSH) in your blood.

Remission is achieved when your immune system stops attacking your thyroid and you no longer have any TRAbs in your blood. Once this happens, your T3 and T4 hormone production will reduce to normal, and the pituitary gland will start its important thermostat function by checking levels in the blood and producing TSH as needed again. These are the key results you need to pay attention to.

TRAbs Level Test

TRAbs is short for Thyroid Stimulating Hormone Receptor Antibodies. As the name suggests, TRAbs are antibodies. Antibodies are produced by the immune system to attack things your body recognises as foreign. In the case of Graves Disease, the immune system is mistakenly sending these TRAbs to attack your thyroid.

The TRAbs test simply measures how many of these antibodies you have circulating in your blood. The more your immune system is attacking your thyroid, the higher your TRAbs level will be. Also, the longer you go undiagnosed for, the higher this number will be. Mine was off the charts. It goes without saying that healthy people do not have any TRAbs present in their blood.

The clinical 'normal' reference range for TRAb is generally undetectable - 0.8U/L. Once you get your blood test back to “undetectable” without requiring anti thyroid drugs you are clinically in remission.

T3 and T4 Level Tests

T3 is short for Triiodothyronine and T4 is short for Thyroxine. They are the main two hormones produced by your thyroid. They are secreted into the blood and are key to the proper running of many of your body’s organs, processes and metabolism.

Your thyroid responds to the attack by the immune system by producing too much T3 and T4. This is known as an overactive thyroid or hyperthyroidism. It is the excessive amounts of these hormones in your body that causes most of the symptoms of Graves’ Disease.

The T3 and T4 tests simply measure how much of these hormones are in your blood.

The clinical 'normal' reference range for T3 is generally 3.5 - 6.5pmol/L. The clinical 'normal' reference range for T4 is generally 10 - 20pmol/L. Once you get these hormones back in range you will start to see relief from your symptoms.

TSH Level Test

TSH is short for Thyroid Stimulating Hormone. It is a hormone produced by the pituitary gland. One of the key roles of the pituitary gland is to regulate the thyroid. When your body needs your thyroid to produce more T3 and T4, the pituitary gland will produce TSH to tell the thyroid to increase ‘production’.

The TSH test simply measures how much TSH you have in your blood. In Graves patients, the attacking antibodies are causing the thyroid to be overactive, so the pituitary gland sees all the extra T3 and T4 circulating in the bloodstream and decides it doesn’t need to produce TSH. As a result, you will have little or no TSH detectable in your blood.

The clinical 'normal' reference range for TSH is generally 0.4 – 4.0mU/L.

Variation Across Labs and Interpretation

It is important to note that blood test reference ranges can vary between different laboratories. This is because different laboratories use different equipment, different testing methods and use different populations of ‘normal’ people to establish a reference range for a given blood test. You should refer to your own blood test results for the references ranges. Finally, this test results guide is for information and education only. Your endocrinologist is the only person who can interpret your results and advise on what the ideal target is for you.