Now that we know what thyroid blood tests need to be run and why, what should the results ideally be if a person is going to be functioning at their highest level? Or, perhaps like so many many people, what do my thyroid test results need to look like for me to know for sure that I have a thyroid problem despite being told over and over again that my thyroid tests look fine. Or, what do my tests results need to look like for me to finally get some really significant positive changes from this thyroid medication someone put me on so long ago?
Before we do that though we need to go over something first. Lets review how a blood work lab report sheet is set up. This is what you see when you look at the report that comes from a testing lab after you have had your blood work done. There are 3 columns of information on the page. In the left column is the name of the specific test being tested. In the middle column is the result of that specific test. In the right column is the “reference range” for that specific test which is sometimes referred to as the “normal range”.
When a test result falls within this reference or “normal range”, a person is typically told that their result is “normal”. When most of the results on the report sheet fall within these reference ranges, a person is typically told “your labs look fine. You’re healthy. You’re great. Don’t worry.”
But a lot of people who are told this think to themselves, “I feel pretty crummy for somebody whose labs say they are healthy. What’s the deal?” Well, the deal is, these reference ranges are not based on where the healthy people are. They are treated like they are but they are not. They are instead based on statistics.
So why are the reference or “normal ranges” based on statistics? Well, the lab companies look at all the results from all the people they have run a specific test on. Some results are low. Some are high. But most are in the middle. The distribution of the results look like a bell shaped curve. Just like about anything that gets tested.
For example, what if we did our own little experiment? What if we wanted to test the height of 100 different people? Some people would be quite short. Some quite tall. But most people would be somewhere in the middle. What if we did our own little experiment and tested the weight of 100 different people? Well, some people would be quite thin. Some quite heavy. But most people would be somewhere in the middle. It’s the same thing as a grading curve in school. A few people will get an “A” on the test. A few will get an “F”. But most people will be somewhere in the middle.
So the lab companies look at this distribution and say “How can we come up with some kind of range to put on this piece of paper? Oh, we know. We will use statistics.” Then, very arbitrarily, the labs also say, “Hey, we know what we can do. Let’s say that the reference range will be everybody who falls within two standard deviation of the mean.” The mean being the results right in the middle of all the results that the lab has gotten from all the people they have tested. Sometimes the lab result sheet will even say this right on the page. It is written as “+/- 2SD.”
In statistics, 95 out of every 100 results will fall within 2 standard deviations of the mean. This is just statistics. Thus no matter who is tested, healthy people, sick people, a bunch of baboons, 5 out of every 100 people tested fall out of the range and 95 people fall in the range. If a test result is flagged as being either high or low (thus out of the range), you know for sure that your result is one of the five worst out of 100. You’re basically an “F”. If a result falls within the range, it simply means you’re not one of the five worst out of 100. You’re not an “F”. But what you’re left with is, you are just someplace between a “D-” and an “A+”.
On any test you ever take in your life, a grade of a “C”or “D” is not an “F”. But it’s certainly not an “A” either. The “A” range is where the body really wants to be. This is where your body will be working best. This “A” range is called the “physiologic range”. Thus, you can be within the reference range but still be very, very far from where you need to be to feel your best. This is a classic reason why interpretation of thyroid results can be so poor.
So, now lets get back to what are the ideal physiologic ranges of the thyroid tests that need to be run. We know the physiologic ranges or “A” ranges because of many, many scientific studies that have been done over many years. These ideal physiologic ranges may change somewhat over time though as we learn more and more about thyroid and its impact on the body. Please know that everyone is a unique individual and test results just help guide decision making. They don’t make the decisions for us.
TSH levels should be less than 2.0 and often times less than 1.0. Free T4 levels in adults should be greater than or equal to 1.0. In a young teenager or preteen, free T4 levels should be greater than or equal to 1.2. In a young child, free T4 levels should be greater than or equal to 1.4. Anything less than these free T4 levels means someone is a poor thyroid producer. The thyroid gland is not making enough T4.
Free T3 levels in adults should be greater than or equal to 3.5. In a young teenager or preteen, levels should be greater than or equal to 4.0. And young children greater than or equal to 4.2.
Reverse T3 levels should be on the very low end of the reference range reported. Between 8 and 10 usually. Anything higher than 8 to 10 on the reverse T3 level means someone is a poor thyroid converter. They are making too much reverse T3 that’s getting in the way of the free T3. Often times, you will see a combination of a lower than ideal free T3 and a higher than ideal reverse T3. Potentially, your free T3 may look ideal. But if reverse T3 is too high, it’s getting in the way and you’re not getting any “bang” for you’re free T3 “effort”. This is being a poor thyroid converter.
Thus, if someone is taking a T4 medicine and is a poor converter, they don’t have enough free T3 and instead have too much reverse T3. When this is happening and the dose of a T4 medicine is increased (due to not feeling great yet), instead of feeling better, a person feels worse. When this happens, you know automatically that the person is a poor thyroid converter. They are taking the extra T4 in the higher dose T4 medicine and turning it into even more reverse T3. The increased reverse T3 is getting in the way of the free T3 even more.
This happens all the time but the reason behind feeling worse on a higher dose of T4 medication is missed. The T4 medicine is typically reduced again to the previous unhelpful dose. Thus, a person can never get to a dose of T4 medication that will help them feel great.
This is where the “desiccated” thyroid medications have the advantage over the T4 medications. Desiccated thyroid medications include “Armour thyroid”, Nature Throid”, “NP thyroid” and “Westhroid”.
It is very hard to heal and feel great without thyroid hormones being where they need to be. Potentially, a person may become such a good thyroid converter that they can stay on their T4 medication and eventually get the “full bang for their T4 effort”. But often, a person will need to change to a desiccated thyroid product in order to heal the body as a whole. Including, fixing the poor thyroid conversion situation. The person can then just stay on the desiccated thyroid product long-term.
I hope this answers the question for you that so many people end up asking which is “Why do I feel so poorly when my thyroid lab tests say I’m fine?” All the correct tests are not being run and the interpretation of the results is not ideal.
I also hope this answers the question for you that so many people end up asking which is “Why do I not feel a whole lot better after starting my T4 thyroid medication.” People can become not just poor thyroid producers but also poor thyroid converters.
And lastly, I hope this allows you to better understand what tests should be run and how the results should be interpreted.
In the next blog post, I will give you the “Signs and symptoms of low thyroid production” sheet which we have talked so much about already. The things that happen when your thyroid hormones are not right.
