woman-sitting-on-mountain-soaking-in-twilight-i-screen

Is rT3 blocking your thyroid function?

In a normal functioning thyroid, the pituitary gland produces TSH - when a healthy thyroid gets this message, it produces two hormones - triiodothyronine (T3) and thyroxine (T4). T4 is converted to T3 on an as-needed basis to regulate metabolic functions.

Your liver also converts T4 to rT3 (reverse T3) which is inactive and actually blocks the action of T3. This is part of the body's normal process to keep your hormones in balance and get rid of unneeded T4. Normally about 40% of T4 is converted to T3 and 20% to rT3. However if the proportion of rT3 dominates then it can produce hypothyroid symptoms, even though your thyroid function test results may appear normal.

runner-resting-on-the-road-i-screen

The balance of rT3 to T3 can be disrupted by a number of factors, most notably because of:

  • an inappropriate response to stress - which can result in too much cortisol, or too little cortisol in the case of Adrenal Fatigue
  • inadequate iron levels
  • other chronic illnesses

Understanding circulating rT3 levels with a reverse T3 test can provide important insights to understand the link between a thyroid disorder or adrenal hormone imbalance.

What we test

Reverse T3 Test (rT3)

Reverse T3 (rT3) is virtually inactive having only 1% the activity of T3 and blocks the action of T3 acting as a metabolic break. Normal metabolism of T4 requires the appropriate balance of T3 to rT3. If the proportion of rT3 dominates then it will antagonise T3 thus producing hypothyroid symptoms despite sufficient circulating levels of T4 and T3.

This reverse T3 test measures:

Reverse triiodothyronine is an isomer of triiodothyronine (T3) which blocks its action.

Test instructions

Print out the pathology form that we email you.

Take your form to your local collection centre to have your sample taken - no need for an appointment.

Results for this test available in 1-2 weeks and will be published in your online dashboard.

Ready. Set. Go!
Buy now for $85 AUD

You may also be interested in

Promotion
Advanced Thyroid Check
5 tests included
$119 AUD
$135 AUD
If you’re looking for a comprehensive assessment of your thyroid function, including an investigation of an underlying autoimmune disorder, then this combined thyroid antibodies test and thyroid function test is the blood test for you.
Best seller
Adrenal Fatigue Check
5 tests included
$139 AUD
Adrenal Fatigue is one of the most under diagnosed condition in western society. This adrenal fatigue test assesses your response to stress and provides valuable insights to help you balance your hormones.
Vitamin B12 Check
1 test included
$59 AUD
Vitamin B12 is an essential vitamin that helps maintain healthy nerves and red blood cells and is also needed to make DNA. This simple vitamin B12 blood test will tell you if you have a deficiency.