American Thyroid Association - Thyroid Hormone Testing overview

[helvella]

Like most documents, this has strengths and weaknesses.

You might find it easier to follow than some. Though some of it really is quite hard for those not already familiar with thyroid issues.

Or more up-to-date (it was published this year - 2024).

And it might provide some useful and quotable material.

For example:

It may take weeks to months for the TSH measurement to accurately reflect thyroid status after an acute change (e.g. change in medication). (Page 3.)

Which is, of course, why we need to switch from TSH (which might have its place for "screening") to FT4 and FT3 testing for dose-adjustments and general management in those who are diagnosed..

Thyroid

Hormones

Consultants:

Katleen Van Uytfanghe, Joel Ehrenkranz, David Halsall, Kelly Hoff, Tze Ping Loh, Carole A. Spencer, and Josef Köhrle;

ATA Thyroid Function Tests Writing Group

Key Points

Interpreting Thyroid Tests

Clinical Thyrotropin Measurements

American Thyroid Association, Inc.

thyroid.org

Physician referral, patient resources available online in English and Spanish.

eguideline.guidelinecentral...?

[asiatic]

It states that T3 is preferred to free T3. Surely that's not correct

[helvella Administrator Thyroid UK in reply to asiatic]

It has been claimed that Free T3 changes too much and too fast to be useful. Whereas Total T3 is more stable.

My view is that is wrong and Total T3 can be very misleading in anyone who has any issues at all with binding proteins. And in those without such issues, Free T3 is a perfectly reasonable and, indeed, preferable choice.

We do see that some labs (I think especially in Scotland) usually do Total T3.

[asiatic in reply to helvella]

I live in Scotland but have fT3 measured ( only because I insist ) I find fT3 always mirrors my symptoms very closely and guides me in making small adjustments to my Levothyroxine to keep me feeling well. I have no experience of Total T3. I don't suppose any research has been done comparing them

[helvella Administrator Thyroid UK in reply to asiatic]

Like so many aspects of thyroid, why not do both Total T3 and Free T3 - maybe in one board/ICB/whatever area in each of the four nations. For a year, or a decade. And then analyse the results.

Actually see how they vary, how well they match symptoms, etc.

[asiatic in reply to helvella]

Totally agree. I would be the first to volunteer😁