What Does Proper Thyroid Testing Reveal? This Is What You Need To Know

Proper thyroid testing makes it far easier to diagnose a potential problem, and helps establish the best way forward with an effective treatment strategy.

Here’s What You Need To Know About Proper Thyroid Testing

To get a proper overview of thyroid function these are the lab tests I recommend:

Thyroid Stimulating Hormone (TSH)

The TSH test is routinely used as a first line test to assess thyroid function. The TSH test is definitely worth doing. However, it really should be done along with other thyroid tests.

For example, a TSH test result makes much more sense when it’s considered along with free thyroxine (T4) and free triiodothyronine (T3).

What Is A Normal Range For TSH?

You may be told your thyroid is fine when your TSH result is in the ‘normal’ range. This may be true to a point when you are interpreting your results using the conventional medical approach.

The problem is, your TSH result can be within the ‘normal’ range despite the fact you have all the symptoms of an under active thyroid!

A very wide reference range is used when testing single TSH. As a consequence, an underlying thyroid issue can be easily missed.

Current research reveals the optimal TSH reference range is 0.5-2.0 mIU/L. However, most labs continue to use the standard reference range of 0.5-5.0 mIU/L.

Are you concerned your TSH is normal but you have a range of low thyroid symptoms?

If this is the case you need to do proper thyroid testing.

A complete thyroid panel includes TSH plus other important thyroid function tests that are listed here below.

What The TSH Test Reveals

Hypothyroidism is associated with a raised TSH. In contrast, a lower than normal TSH result can indicate a hyperthyroid disorder.

The pituitary is the small gland located within your brain that is responsible for producing TSH. It’s important to note a low TSH can also indicate the pituitary gland is struggling to function properly and is therefore not producing adequate TSH. If your doctor suspects you have a disorder called hypopituitarism, they will refer you to an Endocrinologist for further testing.

Free T4 (FT4) and Free T3 (FT3)

A healthy thyroid produces hormones that keep your metabolism humming.  When the thyroid is struggling to keep up with demand both T4 and T3 will be low.

What Free T4 and Free T3 Reveal

The ‘free’ T4 and T3 test is a specific measure of your active thyroid hormones. By testing the free levels you will discover how much of these hormones are circulating, and therefore available for uptake.

When you check free T4 and T3 it also tells you how effectively T4 is converting through to T3. T3 is the thyroid hormone that makes a big difference to how you feel as it’s the thyroid hormone that really powers up your metabolism.

If T3 is low it can indicate a problem with conversion. Under-conversion of T4 to T3 is commonly seen in those with hypothyroidism.

Reverse T3 (RT3)

Under normal conditions T4 converts to both active T3, and inactive reverse T3 (RT3). Your body maintains a healthy balance of T3 and RT3 to help maintain an optimal metabolic rate.

Too much RT3 triggers hypothyroid symptoms, even when TSH, free T4, and T3 appear normal.

The only way to identify excess reverse T3 is by measuring the amount of RT3 in your bloodstream. With this in mind, the RT3 blood test is essential if you want to check for this low thyroid disorder.

What The RT3 Test Reveals

Excess RT3 triggers a hypothyroid disorder termed ‘reverse T3 dominance‘. When you have both free T3 and RT3 you can work out your T3/RT3 ratio to see if this is a problem for you. Too much peripheral conversion of T4 to RT3 can arise in response to strict dieting, adrenal stress, heavy metal exposure, nutrient deficiencies and chronic illness.

To learn more please click here to read: 6 Factors That Set Off Excess Reverse T3. {Could One Or More Apply To You?}

Thyroid Autoantibodies

Thyroid antibody tests are used to diagnose autoimmune thyroid problems as raised thyroid antibodies indicates the thyroid is under autoimmune attack.

These are the two tests;

  • Anti-thyroperoxidase (TPO) antibody test.
    Sometime referred to as the TPO test. This the most common test for autoimmune thyroid disease and is therefore used to diagnose Hashimoto’s, and post pregnancy autoimmune problems.
  • Anti-thyroglobulin antibody (TgAb) test.
    This should be done too as these antibodies target thyroglobulin which is used to form thyroid hormones.

Order The Tests You Want Online

If your doctor is unwilling to authorize comprehensive testing there are two options; find a thyroid-literate doctor who will do a complete thyroid panel, or order the tests you need online.

Here’s what you need to know about ordering tests online in Australia and the USA.

In Australia?

Order your Advanced Thyroid Check from i-screen, Australia. The Advanced Thyroid Check provides an in-depth analysis of thyroid function. It measures TSH, free T4, free T3, thyroid peroxidase (TPO) antibodies, and thyroglobulin antibodies. Add the Reverse T3 Check for AUD$85.

In the USA?

Head on over to True Health Labs website as TrueHealthLabs.com have created the Complete Thyroid Test Panel to give you deeper insights into the complexity of your thyroid health. This popular tests measures: TSH, total T4, total T3, free T4, free T3, reverse T3 (rT3), free T4 index, and TPO and Anti-TG Antibodies to screen for Hashimoto’s.

The Next Step…Interpreting Your Results

Bear in mind, once you have your lab results you will still need help in understanding the results.

A skilled practitioner will interpret the tests in the context of how you feel, your health history, and the symptoms you are experiencing. Furthermore, it’s likely they will use a narrow reference range for each test. This is often different to what’s stated on the pathology report.


  • PubMed Health. Thyroid Function Tests. Link
  • Royal College of Pathologists of Australasia (RCPA) Manual. Pathology Tests. Link

Please note: This post contains affiliate links, to find out more about my affiliate policy please refer to my Terms of Service.


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