Thyroid Test Results – It's All In The Interpretation!

Thyroid test results need to be interpreted in a particular way in order to get the maximum benefit from them. First, let's take a quick look at where the various hormones, involved in thyroid function come from.

The thyroid gland, situated at the front of your neck, is responsible for producing the two primary thyroid hormones, T3 and T4.

The Body Uses Delicately Balanced Feed-Back Loops To Maintain Health

Next, thyroid stimulating hormone (TSH) is a hormone produced by your pituitary gland. This gland – about the size of a peanut - is situated at the base of the brain, and is in turn controlled by the hypothalamus. The latter is another small gland found in our brain, which produces TSH Releasing Hormone (TRH).

This TRH hormone 'talks' to the pituitary when the hypothalamus senses that the thyroid gland is not working at the necessary level to keep all our metabolic functions going at optimal levels.

Normally, the thyroid gland produces about 80% T4 and about 20% T3, yet, of these two hormones, T3 is about four times as active as the T4.


Want To Skip Ahead In This 'Hypothyroidism – Thyroid Test Results Discussion?

The following dialogue will obviously flow more logically if you read it as it unfolds below. However, if you're in a hurry and wish to initially focus on one specific point, then simply click on any of the links in the blue box, directly below, in order to jump ahead.

Good Health Depends On Good Inter-Organ & Glandular Communications
Why Do So Many Doctors Only Use TSH Levels For Diagnosing Thyroid Disorders?
A List Of The Primary Thyroid Results Explored Here
New Reference Ranges For Thyroid Results Still Not Being Acknowledged
Lack Of Proper Diagnosis Means Lack Of Adequate Treatment
Take Back Your Own Power By Asking Some Pertinent Questions
Even The New 2.5 mIU/L Level Is Still Set Too High
Interpretation of The Thyroid Blood Test Results
TSH – Thyroid Stimulating-Hormone
Thyroid Results Showing TSH = High
Thyroid Results Showing TSH = Low
Thyroid Results Showing TSH = Very Low
Thyroid Results Showing Free T4 = High
Thyroid Results Showing Free T4 = Low
Combining The TSH & FT4 Results Can Give More Meaning
Thyroid Results Showing Free T3 = High
Thyroid Results Showing Free T3 = Low
How Does Reverse T3 Fit Into The Thyroid Results?
Thyroid Antibodies
Explaining The Various Thyroid Antibody Tests
Euthyroid – What Does This Mean?
Let's Summarize & Simplify


Good Health Depends On Good Inter-Organ & Glandular Communications

This constant flow of 'conversation' between the hypothalamus, the pituitary, the thyroid, and then back again to the hypothalamus creates a series of finely tuned feed-back loops.

When all the 'members of this orchestra' are tuned in, and responding sensitively to each other, this creates 'melodious music' – or good health; otherwise known as homeostasis.

However, if these glands don't co-operate together as a unit, each wanting to create its own 'music', then things can get quite 'raucous' – ill-health ensues.

Why Do So Many Doctors Only Use TSH Levels For Diagnosing Thyroid Disorders.

If the pituitary gland detects too low a level of those primary thyroid hormones mentioned above, it will send a message to the thyroid gland, via thyroid stimulating hormone (TSH).

Hence raised TSH levels, in thyroid test results, indicate the pituitary is sensing that the thyroid is not doing its job, and therefore sends strong signals to the thyroid gland to ramp up its production of the thyroid hormones T3, and especially T4.

That's why these hormonal signals are called 'TSH – thyroid stimulating hormone'.

From a differential diagnosis perspective, a raised TSH levels is found in what is known as hypothyroidism, while the reverse happens in hyperthyroidism, where the TSH levels will be low.

In other words, in the latter scenario, the pituitary senses that the thyroid gland is producing too much hormone, and needs to signal that gland to slow down its hormone production.

Unfortunately, far too many doctors still believe that they only require a TSH level in order to determine whether a patient requires treatment for thyroid disease, or not.


A List Of The Primary Thyroid Test Results Explored Here

In this section of: '', we'll primarily focus on the:

• TSH levels (thyroid stimulating hormone)

• The T3 (triiodothyronine)

• FT3 (free T3)

• T4 levels (thyroxine)

• FT4 (free T4)

• Thyroid auto-antibodies

• And the rT3 (reverse T3)

Each of these allows for a more accurate differential diagnosis of thyroid disorders, and is a separate component of what is generally known as a thyroid function test.

Thyroid gland function needs to be viewed from this multi-dimensional perspective in order to prevent a wrong diagnosis being made, with the most common misdiagnosis being one of not picking up on the earlier, less 'clinically visible' stages of hypothyroidism.

New Thyroid Test Reference Ranges Still Not Being Acknowledged

The main problem driving this lack of 'clinical visibility' is the fact that most doctors are still using outmoded 'normal ranges', which have in fact been changed quite some years ago.

For instance, till about 2002, the 'normal range' for the TSH levels, used by the majority of laboratories in the USA and Australia was 0.5 to 5.0 mIU/L. Then, in late 2002, early 2003, the American Association of Clinical Endocrinologists (AACE) brought out a new and more focused set of figures, with the upper limit for TSH levels now being set at 3.0 mIU/L.

A portion of the AACE press release of January 2003 states:

'Until November 2002, doctors had relied on a normal TSH level ranging from 0.5 to 5.0 to diagnose and treat patients with a thyroid disorder who tested outside the boundaries of that range. Now AACE encourages doctors to consider treatment for patients who test outside the boundaries of a narrower margin based on a target TSH level of 0.3 to 3.0. AACE believes the new range will result in proper diagnosis for millions of Americans who suffer from a mild thyroid disorder, but have gone untreated until now'.

Unfortunately, far too many labs continue using the thyroid test results for TSH levels set at the old 'normal range' of 0.5 to 5.0 mIU/L.

However, there's an even deeper layer to this entire discussion of what constitutes a 'normal range', which you're highly recommended to read by clicking here.


Lack Of Proper Diagnosis Means Lack Of Adequate Treatment

Sadly, this means that many people world-wide are still not being properly diagnosed when it comes to the more subclinical levels of hypothyroidism – i.e. the earlier phase of an underactive thyroid.

This more subtle level of thyroid disorder can nevertheless create most, if not all of the common symptoms of hypothyroidism. Yet, a wrong diagnosis will occur in many patients because their thyroid test results have been misinterpreted through the use of outdated reference ranges.

Take Back Your Own Power By Asking Some Pertinent Questions

If you've done the 'hypothyroidism quiz', you may feel you do have some degree of this subclinical hypothyroidism, despite your thyroid test results coming back as 'normal'.

If this resonates for you, then you might like to ask your doctor some important questions.

Firstly, it would be important to know exactly what the figure for your TSH levels, found in your thyroid test results came back as.

Secondly, make sure you get to know what 'normal range' is being used by the laboratory doing your thyroid tests.

Thirdly, ask the doctor which 'normal range' they routinely use to diagnose thyroid disorders.

From their answers, you can now determine whether the lab or your doctor have used the more up-to-date figures provided by the AACE, and therefore whether you have been adequately diagnosed for thyroid disease - or not.

Even The New 2.5 mIU/L Level Is Still Set Too High

Indeed, the US National Academy of Clinical Biochemistry, another organization with a say in what is considered 'normal values' for various laboratory tests, has in mind to change them yet again, with the upper limit of 'normality' for the TSH levels now being reduced from 3.0 to 2.5 mIU/L.

Nevertheless, from a naturopathic perspective, even this much lowered 'normal value' of 2.5 mIU/L – compared to the present 5.0 mIU/L ! – is still seen as being the cause of many people with genuine symptoms of hypothyroidism remaining undiagnosed – and therefore untreated.

Hopefully, you can see how the way thyroid tests results are presently interpreted in such an imprecise manner, results in the misdiagnosis of millions of people world-wide. All because too many doctors and laboratories have chosen to not keep up with the latest revisions of 'normal reference ranges' - as advised by various authoritative organizations.


Interpretation of The Thyroid Test Results

Harking back to our discussion above, as well as explored on a previous page, remember, that the TSH secreted by the pituitary is part of the 'brakes' and 'accelerator' used by the various hormonal feedback loops within our system.

The body needs to do this in order to maintain a state of homeostasis – or equilibrium – within the many functions carried out by every gland and organ inside the human organism.

Let's now explore how thyroid gland function can be better understood by breaking the thyroid test results into separate components.

TSH – Thyroid Stimulating-Hormone

This is the one test ordered most often by the greatest majority of doctors when they want to find out whether the thyroid gland is operating normally or not.

The two most likely outcomes of measuring the TSH levels are to diagnose either an underactive thyroid condition – usually termed hypothyroidism – or an overactive thyroid, known as hyperthyroidism.

Hopefully, at this point in the discussion you can see that the accuracy of a thyroid function test depends on how the thyroid test results are interpreted, and hence whether hyper or hypothyroidism is adequately diagnosed or not.

Thyroid Test Results Showing TSH = High

If the TSH levels from the thyroid test results come back as high, this indicates that the feedback loop is 'reading' the blood levels of T4 and T3 thyroid hormones as being inadequate for optimal body function.

This in turn causes the pituitary to try and arouse the thyroid gland to higher function, by secreting more TSH - (remember, 'thyroid stimulating hormone').

The TSH test may be interpreted in different ways, depending on how it combines with varying levels of Free T4, or FT4 (to be discussed in more detail shortly):

• A high TSH + high Free T4 can mean hyperthyroidism (driven by a possible pituitary tumor – but this is rare)

• A high TSH + normal Free T4 can mean mild thyroid gland failure

• A high TSH + low Free T4 means full-on, primary hypothyroidism (here the thyroid gland itself is in a definite state of mal-function)

Thyroid Test Results Showing TSH = Low

If the TSH levels, as dictated by the thyroid test results are too low, this indicates that enough T4 and T3 are circulating, and hence the pituitary is in a sense putting the ‘brakes’ on further T4 or T3 production.

It does this by lowering the amount of TSH secreted, thereby minimizing further stimulation of the thyroid gland in its manufacture of these hormones.


Thyroid Test Results Showing TSH = Very Low

A very low reading could also mean that the person is on prescribed T4 – such as 'Oroxine', 'Thyroxine', 'Levoxyl', 'Levothyroid', 'Unithroid' or 'Synthroid' – in which case the dose may be too high and needs adjustment – always under medical supervision.

Thyroid Test Results Showing Free T4 = High

Let's first explain what the difference is between T4 and FT4 – Free T4.

T4 is the mainly inactive form of thyroid hormone, also known as thyroxine. It contains 4 atoms of iodine, hence the T4.

To convert it to a more active form of thyroid hormone, one atom of iodine needs to be removed, making it into a T3 molecule. However, it's only the Free T4 that can be converted to the more active T3 format – or reverse T3 – rT3. Click here for more information on rT3

Further, this T4 form of the thyroid hormone is found in our bodies in two formats – bound to blood proteins - or unbound. Any such protein-binding makes the T4 particularly inactive – even more so than it inherently is. Some authorities claim that high estrogen levels can increase the extent to which T4 is bound by protein.

Unfortunately, unless specific tests are used, such as the Free T4 (FT4) Test, it's hard to know exactly how much of that T4 being measured is bound – and therefore fully inactive – or unbound, and therefore still partially active.

Next, in regard to the interpretation of Free T4 levels, if the blood test results for Free T4 come back as high, it usually means an overactive thyroid gland, otherwise known as hyperthyroidism, or Graves Disease.

Again, it could also mean that the person with such a result is taking too much medically prescribed thyroid hormone, which will need to be adjusted – but only under medical supervision.

Thyroid Test Results Showing Free T4 = Low

If the Free T4 is too low, this is usually interpreted as indicating an underactive thyroid gland, or hypothyroidism.

It's also possible the body is producing too much of those various binding proteins/globulins mentioned earlier, thereby creating an artificially low level of this hormone.

As mentioned earlier, another possibility is that certain medications, such as the Pill, may be interfering with these thyroid binding globulins, thereby exacerbating any underlying hypothyroid condition even further.

Combining The TSH & FT4 Results Can Give More Meaning

When one considers the thyroid test results, as given by the TSH blood test plus the levels obtained in the FT4 thyroid labs, this can give a greater sense of where thyroid gland function is at.

In other words, if the TSH is raised, but the Free T4 is low, then this can indicate a primary form of thyroid gland malfunction, or primary hypothyroidism.

Here, the thyroid gland itself is seen as being unhealthy, and unable to inherently produce enough thyroid hormone, despite increased stimulation via TSH, or thyroid-stimulating hormone.

However, a too low or too high TSH combined with a too low or too high Free T4 indicates that the pituitary is more likely involved in the formation of any thyroid disease.

Thyroid Test Results Showing Free T3 = High

Just as in the case of T4 being found in either a bound or unbound format, so too do we find the same situation relates to the thyroid hormone T3.

Once more, having a hormone like T3 bound to blood proteins makes it biologically inactive, and hence unable to catalyze metabolic reactions within the cells of our body, especially the production of energy and heat.

Moving on to an interpretation of the Free T3 results, if these return as too high, the cause is most likely an excessive dose of a medically prescribed form of synthetic T3, with this dosage needing to be decreased – but again, only ever under medical supervision!


Thyroid Test Results Showing Free T3 = Low

In contrast, where the Free T3 is too low, this could indicate an underactive thyroid gland, or hypothyroidism.

However, remember that the thyroid produces far more T4 than T3, with most of that T4 needing to be converted to the active T3 format. This process requires a range of nutritional co-factors, including efficiently functioning organs like the liver and kidneys, healthy cell membranes, and so on.

Hence, a blood test showing low levels of T3 is more likely to indicate an inability of the body to enzymatically break down the T4 to T3.

This means that the primary problem is not so much the thyroid gland itself, but rather, has more to do with a secondary, or peripheral aspects to overall thyroid function – in other words, hypothyroidism type 2.

How Does Reverse T3 Fit Into The Thyroid Test Results?

Reverse T3, also known as rT3 is a major player in the hypothyroidism equation. Unfortunately, thus far, when it comes to regular testing for thyroid disorders, modern medicine hasn't really taken on-board how crucial this molecule is in driving thyroid resistance, otherwise known as 'hypothyroidism type 2'.

Understanding how rT3 plays such a major role in sabotaging normal thyroid function, also allows you to better understand how to then treat such resultant hypothyroidism, beyond the far too simplistic approach of prescribing thyroid hormone replacement via drugs such as 'Oroxine', 'Levoxyl', 'Thyroxine', 'Levothyroid', 'Synthroid', 'Unithroid' or 'Liothyronine' ('Cytomel'/'Tertroxin' – a synthetic form of T3).

For further information on what rT3 is, and its importance, please click here and here.

Thyroid Antibodies

Another reason why you may have a lot of the classic symptoms of hypothyroidism, yet your doctor keeps insisting that your regular thyroid function tests are all normal, is because you could be suffering from an autoimmune disease which is affecting the thyroid gland. This requires quite a different set of blood tests to be ordered, besides TSH or T4.

Autoimmunity occurs when your immune system mistakenly starts to attack itself. Which areas it attacks depends on a range of factors, such as genetics, past history of damage to certain organs and glands, thus making them a weakened and easier target... plus there is much we still don't understand about autoimmunity.

One of the main forms of thyroid autoimmunity is called Hashimotos Thyroiditis, and can be an important basis for hypothyroidism symptoms. At this point in time, most doctors believe that this is an incurable form of thyroid deficiency.

However, from a naturopathic perspective, clinical experience proves that viewpoint wrong, with many people suffering from Hashimotos having reversed this condition. How this is done will be explored in greater detail elsewhere on this website. [link still to be activated]

Generally speaking, autoimmune thyroid disease can result in thyroid failure, but the degree of such failure, and hence symptoms, can vary immensely.

Anyone who already has a diagnosis of an autoimmune disorder, such as SLE (systemic lupus erythematosus); rheumatoid arthritis, vitiligo, Sjogrens, or pernicious anemia should automatically be tested for thyroid antibodies too.

In recent times, medicine has acknowledged the relationship between autoimmune thyroid disease and fertility problems. Again, this is an arena in which natural therapeutic approaches have shown their value in allowing people with such thyroid-driven infertility problems to nevertheless fall pregnant.

Explaining The Various Thyroid Antibody Tests

Medicine is able to test for autoimmune thyroid disease, by doing blood tests which look for specific autoantibodies. These come with names such as: TRAb (thyroid stimulating hormone receptor antibody); TPOAb (thyroid peroxidase antibody); anti-TPO (antithyroglobulin antibody) or TgAb (thyroglobulin antibody)... amongst others.

TRAb (thyroid stimulating hormone receptor antibody) is primarily used to see if Graves Disease (hyperthyroidism) exists, or it is used to monitor the severity of Graves Disease - if already diagnosed.

TPOAb (thyroid peroxidase antibodies) are used to check for both Hashimotos thyroiditis and Graves Disease. In the past, these were known as Antimicrosomal Antibodies.

These are important antibodies to check for as they sabotage the effectiveness of Thyroid Peroxidase, an enzyme which helps convert the largely inactive T4 to the far more active T3 format.

The thyroid peroxidase antibodies are significantly elevated in Hashimotos Thyroiditis, as well as Graves Disease.

TgAb (thyroglobulin antibody) is important to test for in those who have thyroid cancer. The presence of these antibodies indicates that using thyroglobulin as a monitoring tool in thyroid cancer is going to be problematic.

Thyroglobulin antibodies can also be raised in Graves Disease or thyroiditis (inflammation of the thyroid), and high levels found in diagnosed Graves Disease are indicative of a higher likelihood of eventually going from a hyper to a hypothyroid state.

Thyroid-Stimulating Immunoglobulins (TSI) [Consisting of TSH Stimulating Antibodies (TSAb) and TSH receptor antibodies (TRAb)].

These are found in many patients who have a history of Graves disease, and can be used to measure the severity of this condition.


Euthyroid – What Does This Mean?

You will often hear the term 'euthyroid' mentioned in thyroid test results – it simply means that within medicine’s present model of normality, the thyroid gland is considered to be producing sufficient hormones, and therefore is seen as healthy.

Let's Summarize & Simplify

If your head is spinning after reading the many variations-on-a-theme that are possible when trying to interpret the rather large array of thyroid test results... then you wouldn't be the first!

So, let's try to simplify some of the above information, by putting it into a succinct table format.

TSH FT4 FT3 Most Likely Explanation
high high high hyperthyroidism-? pituitary tumor
low low low secondary hypothyroidism-? pituitary failure
high normal normal mild subclinical hypothyroidism
high low low primary, full-blown hypothyroidism
very low high high ? on replacement therapy–or hyperthyroidism
low normal normal mild hyperthyroidism
high normal low ? secondary hypothyroidism


As you can see from the above discussion, interpreting thyroid test results can lead you into a bit of a mine-field!

However, hopefully you now do have at least a bit more of a clear understanding as to why so many people keep being told their thyroid is 'normal', despite them suffering from many of the classic hypothyroidism symptoms.

Nevertheless, having explored the various factors arising from this diagnostic dilemma should allow you to feel more empowered, as you're now better placed to understand your own thyroid test results.

"Knowledge empowers; intuition guides – both are needed to succeed in Life's Journey"

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