I’ve been treated for an underactive thyroid for well over twenty years and still am not very understanding of the blood test results! I’m just wondering if someone could help me with my latest results. I’m on 125mcg of levothyroxine & have been on the same dose for a long time.
TSH 0.009 (0.34 - 5.6)
Serum Free T4 18.9 (7.7 - 15.1)
Serum Free T3 4.3 (4.3 - 6.8)
My registered GP said these results are fine but I’ve just been to see another GP for an unrelated issue & she has advised me to reduce my dose of medication. What do I do? I feel absolutely fine!
Any advice would be welcomed!
Sarah.
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Sarahlouise1980
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I can understand why the second GP said to reduce your medication.
We always say here that the aim of a treated Hypo patient, generally, is for TSH to be 1 or below with FT4 and FT3 in the upper part of their reference ranges, if that is where you feel well.
Most doctors are unhappy with TSH suppressed (suppressed = less than 0.1). They think that suppressed TSH = overmedication; however, TSH is not a thyroid hormone, it's a pituitary hormone and this is useful for diagnosis. Once on thyroid hormone replacement it's the thyroid hormones - FT4 and FT3 - which tell us our thyroid status and that's what they should be looking at but they're not taught that.
Looking at your results, your TSH is suppressed and your FT4 is over range at 151.35%, it's the suppressed TSH and very high FT4 that the second GP doesn't like. However, your FT3 is at the very bottom limit of the range. This is showing that you are not converting T4 into T3. I'm actually surprised that you feel well because it's low T3 that causes symptoms.
What your results show is that you could benefit from less Levo (to bring your FT4 down) and the introduction of some T3 because you're not producing any yourself. I believe an endo who specialises in thyroid (rather than diabetes) would recognise this but I'm doubtful that most GPs would as they seem to have little understanding of thyroid and how to interpret results.
What are your nutrient levels like? We need optimal nutrient levels for conversion of T4 to T3 so you need to test
The concern is that most GP's think a low TSH means an increased risk of osteoporosis, and Atrial Fibrilation, but this is mostly based on the inaccurate rubbish they are taught about thyroid treatment.
If you feel very well , i'd leave your dose as it is for now while you learn more about it for yourself. Very often people are asked to reduce when feeling well, because a GP doesn't like the numbers, then they feel less well and it's not always possible to get back to how well they felt before, even if they later put the dose back.
If you feel fine, that's the most important thing. And, your doctors obviously don't know very much about thyroid, either! lol So, I'll try and explain...
The thyroid hormones are called T4 and T3. There are two types of T4 and T3: bound (to carrier proteins, that take them round in the blood to where they're needed) and unbound. What interests us is the unbound type, what we call Free T4 and Free T3 (FT4 and FT3)
T4 is basically a storage hormone, that doesn't do very much until it is converted into T3, the active hormone. And, it's T3 that causes symptoms when it's too high or too low.
So, the most important number is the FT3.
Unfortunately, doctors don't know this - very bad education in med school. They think that the most important number is the TSH. But, the TSH isn't even a thyroid hormone, it is made in the pituitary.
When the pituitary - which is located in the brain - senses that there is not enough thyroid hormone in the blood, it increases the production of TSH to stimulate the thyroid to make more hormone. When it senses there is enough, it reduces production. That's how a healthy pituitary and thyroid work together.
But, when you have any sort of thyroid or pituitary problem, this system doesn't work so well. The TSH can become low or suppressed with quite modest amounts of thyroid hormone. But, because doctors have such limited knowledge of unhealthy thyroids, they believe that the low TSH is telling them that you're taking too much exogenous hormone - levo, or whatever. And, they have been taught that a low TSH is dangerous and can cause heart problems and osteoporosis - none of which is true, but that's a story for another time.
So, instead of looking at the FT3, as they should, they only look at the TSH and draw the wrong conclusions.
So, if we look at your results:
TSH 0.009 (0.34 - 5.6)
Serum Free T4 18.9 (7.7 - 15.1)
Serum Free T3 4.3 (4.3 - 6.8)
We see that your TSH is very low - suppressed. A euthyroid (normal) TSH is around 1.
And, we see that your FT4 is quite a bit over-range, which is why your TSH is suppressed.
BUT, your FT3, the active hormone, is right at the bottom of the range.
So, how do we put those bits of information together, Well, a I said, FT4 is very high, so TSH is low. But, why is the FT3 also low? Because you are what we call a poor converter. Your body is having a lot of trouble converting your T4 - storage hormone - to the active hormone T3.
Why? Well, it could be because your TSH is so low. The TSH has two jobs - and only two, as far as we know. a) it stimulates the thyroid to make more hormone b) it stimulates the enzymes that do the conversion of T4 to T3 (laymans terms, I'm trying to keep this simple )
So, it is possible that if you did reduce your dose of levo, the TSH would rise enough to improve conversion.
But, poor conversion can also be due to a lot of other things, like low nutrients. So, have you had your vit D, vit B12, folate and ferritin tested? If not, that should be your next step, to get those tested.
In the meantime, You could try reducing your levo by 25 mcg, and retest in six weeks, and see what happens, and how you feel. It's probably not a good thing to have such a high FT4, but we don't really know. It's all down to personel experimentation to see what works for you.
Always test thyroid levels as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test
Which brand of levothyroxine are you currently taking
Do you always get same brand levothyroxine at each prescription
What vitamin supplements are you currently taking
ESSENTIAL to regularly retest vitamin D, folate, ferritin and B12 at least once year
Come back with new post once you get full results and ranges
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Can anyone help me interpret my thyroid test results please?
