Thyroid UK
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T4 higher but other results normal - why?

7 months ago my bloods were:

T3 1.00 ng/ml - range 0.58 - 1.59 ng/ml

Free T4 1.21 ng/dl range 0.82 - 1.51

TSH 1.41 ulU/mL range 0.25-5.0 ulU/ml

I upped my levothyroxine from 75mg to 100mg and have felt OK.

Today's results:

T3 1.00 ng/ml - range 0.58 - 1.59 ng/ml

T4 7.07 ug/dl - range 4.50 - 12.00 ug/dl

Free T4 1.76 ng/dl range 0.82 - 1.51

TSH 0.94 ulU/mL range 0.25-5.0 ulU/ml

Thyroglobulin 6.61 ng/mL - range 0.0 - 55.00 ng/ mL

I see the T4 is higher but the T3 has stayed the same. I'm not sure whether to go back to 75mg or stay on 100mg.

I have put on weight over the last few months so I'm hesitant to go down unless it's needed.

I have a single nodule that is 6.8 x 5.4 mms - it has gradually grown over the last few years but as you can see, it's still very small.

Any comments would be very helpful.


p.s. I don't currently live in the UK and I have to control it myself, pretty much as the endocrinologists where I live are a bit hit and miss!

7 Replies

Well, the thing is, you're not testing the right T3 there. Those are Total T3s, and what you need is the FT3. You cannot compare a TT3 with an FT4, it's like comparing apples and oranges.

If you tested the FT3, I think you will find that you have a conversion problem, and that's why your FT4 has gone up, but your T3 doesn't appear to.


Thanks greygoose - I did ask for Free T3 but it never came up on the indication from the doctor. I don't think they've ever tested my free T3... anywhere!


Your doctor probably doesn't know the difference. But you're certainly not going to get any useful information with a TT3.


I agree with GG there and it's likely you have a conversion problem. Taking extra medication won't help much so you need to check Vit D, B12, folate and ferritin as they help. They need to be optimal not just in range.

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I'm still taking my B12 as that was low when I was tested 7 months ago. I haven't tested my vitamin D but I'd be surprised if that was low as I live in the Caribbean.

I'm thinking I should take some selenium to help with conversion.


After living in Crete for a few years - both hubby and I tested *insufficient* for VitD. Apparently we do not process it as well when we are older. Apologies if you are young !


Not sure about that. I have read that if you get a tan the suns rays can't penetrate so you don't get the Vit D you're expectiving and if you have dark skin the same problem.

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