Expert Advice From Louise O’Connor, Australian Naturopath + Wellness Coach { About the book }

The Top 5 Thyroid Blood Tests. These Thyroid Tests Are Essential. Find Out Why!

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top 5 thyroid blood testsThe top 5 thyroid blood tests I recommend will help reveal how well your thyroid is working. Also discover why you need to check more than TSH.

For most people the standard thyroid test used to assess their thyroid health is the thyroid stimulating hormone (TSH) test. This test measures the amount of TSH circulating in your bloodstream.

TSH is a thyroid hormone however it is not actually produced by the thyroid. It is produced by the pituitary gland located deep within the brain.

When TSH is released by the pituitary gland it travels to the thyroid via the bloodstream to signal to the thyroid to get busy making your essential thyroid hormones.

The two main hormones produced by the thyroid are: thyroxine (T4) and triiodothyronine (T3). Greater quantities of TSH are released when the body requires more T4 and T3.

Could you have an underactive thyroid despite having a ‘normal’ TSH?

Testing thyroid health status is controversial. Due to restraints within the medical system the stand alone TSH test is regarded as the gold standard to check your thyroid health.

Individuals are often advised no further investigation is necessary when their TSH test result falls within the acceptable reference range. This can be despite the fact they are displaying the typical signs of a thyroid in crisis.

A TSH test result may appear ‘normal’ but this can be misleading and does not automatically rule out a low thyroid issue.

Simply testing TSH also raises questions about what level should be considered adequate and the validity of using a wide reference range. Current research shows TSH between 0.5 and 2.0 mIU/L is ideal.

What are the top thyroid tests?

A single test of TSH is often inadequate.  If you suspect your thyroid is underactive it is a good idea to discuss comprehensive thyroid testing with a skilled healthcare practitioner.

Testing more than TSH will help reveal how well your thyroid is actually working and is useful to monitor your thyroid health recovery.

Comprehensive testing includes an evaluation of the key thyroid hormones. Testing free T4 and T3 provides clues as to how much of these hormones are ‘free’ and available for uptake and use throughout the body. If you rely on simply testing TSH alone and do not measure these two main thyroid hormones you are missing critical parts of the puzzle.

In addition, when you assess the amount of circulating T4 and T3 in the bloodstream it provides an overall picture of how much T4 is converting to the more potent T3. For many people with a thyroid problem their bodies are not converting T4 effectively through to T3.

When T3 levels rise it is usual to notice improvements in low thyroid symptoms. T3 helps stimulate metabolism which has far-reaching effects in the body including sparking energy metabolism, fat burning for weight loss and reducing thyroid hair loss.

Under normal conditions your body converts T4 to both T3 and ‘reverse T3’, which has the opposite effects of T3. The body quickly eliminates reverse T3 if it is not required to put the brakes on metabolism. Low T3 can indicate T4 is not converting effectively to T3 and may in fact be creating excess amounts of reverse T3.

Too much reverse T3 is rapidly produced when you are under enormous stress. This then leads to the common symptoms of a sluggish thyroid. Only a specific test for reverse T3 can identify high levels of this inactive form of T3. Reverse T3 dominance syndrome is diagnosed when reverse T3 remains elevated.

Evaluating thyroid antibodies levels will confirm an active thyroid autoimmune disorder. Most commonly elevated levels of thyroid antibodies are associated with Hashimoto’s thyroiditis which is a chronic inflammatory condition of the thyroid.

In summary, the top 5 thyroid blood tests I recommend are:

  • thyroid stimulating hormone (TSH)
  • free T4 (FT4)
  • free T3 (FT3)
  • thyroid antibodies
  • reverse T3 (RT3)

When discussing getting thyroid blood tests  you should also mention if you have a family history of thyroid problems and definitely list your thyroid related symptoms.

Low thyroid symptoms are significant indicators that your thyroid is not working well and should not be ignored.

The most common low thyroid symptoms include fatigue, feeling the cold, dry skin and hair, low libido, weight gain, menstrual irregularities, mood changes, low blood pressure, heart palpitations, hair loss and muscle weakness. Your individual symptoms should be carefully considered along with the thyroid blood test results.

You may also want to mention if you have had any serious infections such as hepatitis, Epstein-Barr virus or cytomegalovirus. These viruses are often linked to chronic fatigue syndrome. It is not unusual to see raised reverse T3 levels in response to chronic illness.

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  1. Laurel Broclkebank says:

    Thank you for your email. Looking at my last results in August my TSH was 3.1

    • Louise O'Connor says:

      Research indicates a TSH of less than 2.0 is ideal. TSH should also be taken into account with free T4 + T3. Testing thyroid antibodies will also screen you for Hashi. All women with underactive thyroid symptoms should be checked for this autoimmune issue as it is the leading cause of hypothyroidism in women.

  2. Boni Bromley says:

    I have had fluctuating TSH levels where I have been told I have either been overdosed or underdosed. I have asked for the full test but am told just to change the dose.
    I still have all the symptoms especially weight gain, hair loss, dry skin, brittle nails, cannot concentrate and extreme fatigue. I am told that this is normal once one start getting older, I am 68 now but have had this for many years. Constant requests for proper testing but with no luck. I often wonder if I even need to be on Thyroxine and if in fact it is damaging my health.
    Oh I have been offered antidepressants – I said no!

    • Louise O'Connor says:

      Hi Boni, I suggest you find a doctor or Naturopath who will do comprehensive testing. It’s very important to get all 5 thyroid tests done. Testing free T3 is particularly important as you get older as it’s crucial for heart and brain function. The symptoms you list are often associated with low T3. Some doctors prescribe a combination of T4 and T3 which often works more effectively than single T4. Best wishes, Louise O’Connor

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