Thyroid UK
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Is FT3 testing more common than TT3 testing on the NHS? What's the norm where you are?

Hello again folks,

Sorry for the many posts recently, I'm thinking a lot about my health and that is giving rise to questions.

So, whenever I've gotten a T3 test from the NHS they have automatically tested TT3, I have asked my GP, and the 2 endos I've seen, for FT3 testing, and all seem surprised by this request and say they don't do it as it isn't a useful indicator of T3 levels. My Endo has now agreed to do a FT3 test but I have to phone him before I come to my appointment so that he can make a special arrangement with the lab (however, next appointment is 3 months away so I've got a private test to do).

However, whenever I've posted my results on here people seem surprised that TT3 has been tested instead of FT3.

So is FT3 the norm on the NHS for other people? If so, which part of the UK are you in (if you don't mind me asking)?

Could it be because I am in Scotland, could the practises be different here? Is anyone else here from Scotland? Have you had trouble getting FT3 tested?

Thanks for reading.

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I am in Wales and have had quite a few FT3 tests done through my surgery and endo when I saw one (they seem to get done automatically when TSH is suppressed). I've never had TT3 done through GP surgery nor the few times I saw an endo.

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Thanks SeasideSusie :)

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From South England - I have FT3 tests regularly by NHS endo - for over 15 yrs. GP is not allowed to get them - he requests but they always ignore.

Never once had a TT3 test :-)

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Thanks Saggyuk :)

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In fact it's rather ridiculous. I'd seen the endo every six months for over 10 yrs as never could get grip on health but he discharged me when everything cleared up after going gluten free.

The next test I did with GP came back as TSH 16.85 T4 <3.2 - he said "well all I'm able to determine from this is that you're probably dead or in the process of dying - you're clearly not"!

They still refused the GPs request for a T3 test even with other results like that lol.

He had to refer me back after six months and now the endo is unable to discharge me purely because no one else can request the tests required lol!!!!

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I think the norm for diagnosing in the UK is TSH and T4. However, you will see in the link below what all the tests mean and why FT4 and FT3 are important.

thyroiduk.org.uk/tuk/testin...

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Thanks shaws :)

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kittenmittens,

Some years ago I looked at the websites of a number of NHS pathology laboratories. They varied: some did TT3, others FT3.

A very quick search suggests that this variation still exists - though perhaps some labs have changed?

[Edited to clarify - these are UK NHS labs.]

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Ah, so it is maybe a lab variation rather than a country variation.

Thanks Helvella, most helpful.

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kittenmittens,

Just did a very quick (dirty and unreliable) pair of searches.

pathology lab tt3 site:.nhs.uk = 13 hits

pathology lab ft3 site:.nhs.uk = 306 hits

This mustn't be taken as any sort of proof. We need to go through every significant lab and check each one. Some might even do both! Some might spell them out in full, or use a code (rather than the abbreviations I used). And the abbreviations could possibly be used for something else entirely. (I was going to suggest postcodes - there is TF3 for Telford but no FT3.)

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Hmm, even though that's just a rough check it would explain why people are always so surprised when I post TT3 results over FT3 results, and the few comments I've had here (very, very small sample size!) so far seem to indicate that FT3 is more often the norm.

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Did a search for Glasgow Pathology Lab, found what one Glasgow NHS services use, it's in the same hospital as my Endo. No results for Glasgow Pathology lab TT3/FT3/Total T3/Free T3. But I can safely assume that their normal test is going to be TT3, and that my GP and Endo use that lab, hence, why my TT3 is always tested. I shall be trying to get endo to test FT3 from now on (have to remember to call him first to arrange it), although I'm not sure how often I'll be seeing endo now as he seems to be at rather a loss with what to do with me.

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I'm also in Wales, and have Graves'. My endo orders TSH, FT3 and FT4 tests every 4-6 weeks, and they are always done, even when TSH and FT4 have been within range. So far as I know, I've never had TT3 tested.

My GP surgery managed to lose the test envelope provided by the endo once, so the GP had to write out a new one. She was worried that the lab might not do the FT3 test, although she did request it, and the result came back ok.

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Thanks Valarian :)

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I am in Scotland.

GP always asked for FT3 as well as TSH and FT4 because I am Graves but now hypo after RAI. Lab usually ignored the request. However, like Seaside Susie, as soon as my TSH became suppressed Lab tests for FT3 every time now. In fact last bloods came back with TSH and FT3 result and FT4 wasn’t tested. Now that I take Levo it’s FT3 that I am more interested in even if GP is getting hung up on FT4 and good old TSH.

Only time I saw TT3 figures was years ago when I was in hospital with thyroid storm and consultant Endo was doing blood tests daily.

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Ah, yes, I'm thinking after seeing Helvella's response that it is maybe a lab variation rather than a Country variation.

Thanks MrsGraves.

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My USA endo orders tt3 and insists that ft3 is unreliable. My GP orders ft3. All other doctors I've had didn't want to test t3 at all.

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kittenmittens,

I have seen claims that FT3 varies so much during the day that it is why it is unreliable.

I have seen claims that TT3 better reflects the "average" T3 levels.

I suspect that if TT3 ever has any such benefit, it could only be when changes are observed and not the absolute number. Otherwise it will very much be reflecting the binding capacity of the blood rather than anything useful to do with T3. Even then, it would be based on the assumption that nothing else is significantly affecting binding capacity.

In some idyllic future, our FT3 would be continuously monitored and we'd know exactly what is happening to it. :-)

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