Thyroid UK
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New Labs - conflicting interpretation

Hello all - been quite a while since I have posted, although I do lurk and learn.

I just got my first "complete" thyroid lab panel and the results seem good to me, after a year on first Euthyroid for a few months, then W-throid (NDT) which I requested as I do not trust synthetically manufactured replacements. Problem is the Doc that ordered the labs says the Reverse T3 is fine, but another Functional Medicine Doc says it is "pooling" (I don't even know what that means) - probably because of low DHEA (19).

I am only taking half a tablet (1gr) daily -seems enough

Here are the labs - hope someone can lend some insight about the RT3

Thyroid antibody test: normal

TPO <10 <=34IU/mL

TGA <20 =<=40IU/mL

Regular panel:

result range

TSH 1.53 0.45-4.50mU/L

*down from 5.8 a year ago

T3 tot108 80-200ng/dL

FT3 2.8 2.0-4.8pg/mL

FT4 1.4 0.8-1.7ng/dL

RT3 16 (LC/MS/MS) 8-25ng/dL

4 Replies


T4 converts to T3 and rT3. rT3 is the body's brake on converting to too much T3. Yours is mid-range so it isn't high. High levels of T4 which are not converting to T3 are sometimes said to be 'pooling' and causing high rT3. I've not heard that rT3 pools.

If you feel well on 1/2 grain fine. If not, there is scope to increase dose to raise FT3 and reduce TSH.


Thanks! I am also addressing low DHEA so will not change W-throid until I see some results from the adaptogenics I have started taking for that. It seems that any of the thyroid meds cause fluctuations in blood sugar, so as a diabetic, I am not anxious to increase unless really necessary. My current level of fatigue is likely due to the low DHEA as well as very low Glutathione - I was just wondering about the difference in interpretations - both doctors are Functional Medicine practitioners.



Well I think the FD who talked about 'pooling' was wrong. There's so little T4 in 1/2 grain that it is most unlikely that anyone taking it would have unconverted T4 pooling or causing high rT3.

It is often necessary to check blood sugar and thyroid levels when adjusting either Metformin or thyroid replacement.

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Hi mcenerny -

rT3 needs to be evaluated in context with FT3, the ratio matters.

If I have used the calculator right, your ratio is 17, above 20 is good.

Here's the calculator, an explanation of what pooling means and links to further explanations and things to consider:

Hope that helps!

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