Thyroid UK

My blood results after 3 months on levo

TSH 0.16 miu/L (0.2 - 4.2)

Free T4 19.9 pool/L. (12 - 22)

My doctor was very pleased with this result and suggested I stay on the dose of 100mcg of levothyroxine. My previous results were TSH 7.11 and T4 10.8

Is this latest result a good one?

Anyone advise a good book I can buy that explains very easily all about underactive thyroid please. Thank you

7 Replies

I would say that it is good. Although the ultimate test is how do you feel? TSH and T4 don't tell the whole story. T3 is the test that really shows how much usable hormone we have. So the other tests can look great, but T3 could still be rock bottom if you are bad at converting T4 to T3. If you are feeling much better then you probably don't have a conversion problem. In which case you are on the right dose.

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I did do my own private T3 blood test which I understand is good. It was 4.48 and the normal range is 3.1 - 6.8 so from what little I understand this is good and I am feeling so much better so will leave it as it is and keep on 100mcg levo. Thank you so much, just good to ask others


Those results look very good to me but it's how you feel that is important. I'm impressed that your doctor didn't freak out about your TSH being slightly below range. That is just about ideal for a lot of people on thyroxine :)

I'm not sure about books but the main Thyroid UK website has some useful resources like this page.

You can get to more information using the purple menu bar on the left of the page.

I hope that helps.

Carolyn x


Thank you CarolynB, as I am new to this condition I wanted to just make sure I am on the right path to recovery with the blood results. This forum site is so wonderful.

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"Understanding Thyroid disorders"by Dr Anthony Toft, is a concise little book that's a vg starting point. You can buy it in most pharmacies or amazon/ebay uk & costs less than £5. x


Thank you, will see if I can purchase this. My doctor was explaining about T4 and TSH this morning but she lost me really as I wasn't understanding what she was saying. Silly me, need to read up.


Philly, Results look good to me too :)

TSH is a pituitary hormone.

Thryoxine (T4) is a pro-hormone which is converted to T3 in the major organs, brain, liver, kidneys and heart.

Triiodothyronine (T3) is the active hormone which causes hypothyroid symptoms when low.

When pituitary gland detects low circulating hormone it produces TSH to stimulate the thyroid gland to produce more T4 for conversion to T3. So, TSH rises when T4 and T3 are low and drops again when T4 and T3 levels are adequate/high.


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