T4 conversion

[Anne-B]

What results give an indication that you are not converting T4 to T3 well?

[diogenes Remembering]

If on T4 only, a T4/T3 ratio of over 4.5/1 indicates inferior conversion. You can't do that calculation if you are taking T3 as well.

[Anne-B in reply to diogenes]

Thank you. I did think my T3 result would be required. My GP said I was converting fine but he only had my TSH and T4 result!

I'm very angry 😡 doctor lying to me doesn't instil trust in him.

I have an appointment with head of my GP practise on Thursday so will see how it goes.

[AmandaK in reply to diogenes]

Is the ratio the same if no thyroid meds are taken (i.e. if someone is considered by the medical profession as euthyroid so not treated despite being symptomatic)?

[diogenes Remembering in reply to AmandaK]

Not necessarily. When healthy, poorer converters use the active thyroid gland direct to augment the T3 directly, so as to help out the inferior body T4-T3 conversion.

[AmandaK in reply to diogenes]

Thank you for this - not sure then what to make of the results of the urine test for T4-T3 conversion I'm about to receive!

[SeasideSusie Remembering in reply to diogenes]

Has that changed diogenes as I remember you used to quote 4:1

[diogenes Remembering in reply to SeasideSusie]

No not really. I was being conservative. Of course like everything else, one condition shades into another and you can't draw a hard line between.

[SeasideSusie Remembering in reply to diogenes]

Thanks John. I remember member Eljii used to quote 3:1 but can't remember if she had any references and I don't think she's a member now.

[Clutter]

Anne-B,

When taking Levothyroxine only if TSH is low, FT4 high and FT3 low it indicates poor conversion.

[Anne-B in reply to Clutter]

Thank you for your help. I only have FT4 result so can't tell even though GP said I was converting fine! Only taking levothyroxine. My next step is to ask for full blood test.

[Clutter in reply to Anne-B]

Anne-B,

Without FT3 done at the same time as TSH and FT4 GP can't possibly say for sure that your conversion is fine. FT3 is rarely tested in primary care unless TSH is suppressed <0.03. If you want FT3 tested you may have to order a private thyroid test via thyroiduk.org.uk/tuk/testin... Medichecks offer #ThyroidThursday discounts.

[JGBH in reply to Anne-B]

Anne-B

If possible take a friend with you at your next appointment as a witness. Then clearly say you are aware that only testing TSH value is simply not enough to test for hypothyroidism and having a clear picture of situation. A thyroid panel is required and comprises: TSH, FT4, FT3 and antibodies. Insist firmly but politely it is what you want. She may say the Lab won't do it... BUT simply say Please TRY. This is what happened with me and to my surprise everything was tested except for the thyroglobulin antibody which the NHS does not do... ((I wonder why), only the thyroid peroxydase antibody was tested. But that will give you an idea of whether you convert well or not T4 to T3. Of course you can do private tests which will be complete. Also as often advised by members of forum, do not take Levo for 24 hours, test early in morning (before 8 am) fasting,only drink water and take levo straight after test. Do not let GP intimidate you, keep calm but be insistent until you get what you want and need. Please let us know how it went and good luck.

[Anne-B in reply to JGBH]

thank you, your advice is really helpful. I will keep you posted. 😀

[ann_g_k]

Genova Diagnostics do a 24hr urine testing (test END08) to test FT4 and FT3 to determine whether or not conversion is taking place. I notice that this is FT4 and FT3 not T4 and T3 so I'm not sure what difference this makes.

You would need to book the test through the ThyroidUK website and use the TUK code.

[SeasideSusie Remembering in reply to ann_g_k]

It tests T3/T4, no mention of FT3/FT4 gdx.net/uk/product/urine-th...

[Anne-B in reply to SeasideSusie]

What's the difference between T4/T3 and FT4/FT3?

[SeasideSusie Remembering in reply to Anne-B]

From verywell.com/interpret-your... - worth reading it all

"Total T4 measures the total amount of thyroxine circulating in the bloodstream. Free T4 measures the available, unbound amount of thyroxine in the bloodstream."

[AmandaK in reply to SeasideSusie]

Well, I'm confused as on the form I was sent by Genova (I've just carried out the urine test), it stated FT3 and FT4 not T3 and T4, which is why I queried it.

We'll see what the results say.

[diogenes Remembering in reply to AmandaK]

The reason is that the T4 and T3 in urine is supposed to be an indirect measure of the FT4 and FT3 in blood not total hormones. However its not very accurate and misleads if there is anything wrong with the kidney's functioning. Excess protein in urine is an interferent for example.

[SeasideSusie Remembering in reply to AmandaK]

Let us know Amanda and if possible post a picture of the result sheet (you'll need to start a new thread to post a picture).

I'll be interested to see if it's been changed. I have done 4 urine tests, the last one being November 2016 and all of them have said the same:

Triiodothyronine T3

Thyroxine T4

T3:T4 ratio

So no mention of FT3/FT4 on any of my results, nor in their current description of the test on their website.

I'm not sure whether it's important that it's total or free with a urine test. I've used it for monitoring what's happened since discovering my poor conversion, which the urine test confirmed after the blood test showed this. Since adding T3 and lowering Levo, the follow up urine tests have shown how much more T3 there is (increasing as dose has been increased) so it's been a very useful exercise.

[ann_g_k in reply to SeasideSusie]

Hi Seaside Susie, I've just phoned Genova and have been assured that the info on the website is correct and the info on the form I was sent with the kit is incorrect so it's just as well this has been flagged up!

They said they would amend the form as obviously it is misleading and causing confusion.

[SeasideSusie Remembering in reply to ann_g_k]

Thank you Ann. It makes you wonder how such a blunder goes unnoticed with these companies!!!