Can you be hypothyroid with normal Free T4 and Free T3 just Tsh high?

[richard123]

Can you be hypothyroid with normal upper range Free T4 and Free T3 just Tsh high? Just trying to understand this!!!

[shaws Administrator]

I think with a high TSH and clinical symptoms you are hypo. A high T3 in other countries is above 3+ with symptoms. In the UK, a TSH of 10 is required. I believe they only check T4 along with the TSH in the UK.

thyroiduk.org.uk/tuk/about_...

[greygoose]

Have you got the actual number and ranges? Just saying 'normal' is meaningless.

[Treepie]

I am puzzled .You have been a member of this forumfor five years .Do you ever read other folks posts?

[richard123]

Yes all the time! You? Any useful comments to mine and anyone else's posts treepie 🤔

[richard123]

Maybe puzzled like me another symptom of mine

[Hidden]

Please post your results and ranges and someone will help.

[eeng]

I think the answer to your question is that if your FT3 and FT4 are in the upper part of the range the chances of you being hypothyroid are quite low. There are several scenarios that might produce a 'high TSH, good FT3, FT4' scenario.

1 If you are having a 'hashi's flare' where levels of FT3 and FT4 can become high briefly but the pituitary might not have noticed so the TSH might still be high (not likely but theoretically possible). This would indicate that the thyroid is under autoimmune attack, and would be a precursor to hypothyroidism.

2 A pituitary problem where the pituitary is producing too much TSH for reasons best known to itself but not related to a thyroid problem (e.g. a TSH-secreting tumour on the pituitary -very rare, but possible)

3. An infection at the time of the blood test - I have heard that certain infections can raise TSH - this is why before a hypothyroid diagnosis in the UK we need two blood tests showing a high TSH 3 months apart.

4. If you take Levothyroxine shortly before the blood test your FT4 and FT3 may be artificially high, although your TSH might still be representative of your thyroid status.

I hope this answers your question. Maybe some other members will come up with some other theoretically possible scenarios. In cases 1, 3 and 4 a repeat blood test should be informative.

[richard123]

Thank you for your reply, I have very high TPO range 0-40 mine is 580. I was unwell with flu when diagnosed but Tsh had been creeping up for previous year at least. I remember my TSH being 25 and when asked how I was I felt very well!

When I had next test with flu it was 30 and I felt awful

Gp did not treat earlier as T4 has always been fine. T4 has remained at top end of normal with treatment as it was before treatment.

The endo mentioned assay interference due to high antibodies and thyroid hormone resistance and suggests I reduce thyroxine but although I feel rough I'm not as rough as I was but then I had flu and was very slow recovering so I couldn't work out what was what

As advised on here I always do bloods early and do not take thyroxine on the morning of test.

[LAHs]

Yes! It depends upon WHO is calling WHAT "normal". Post your results.