Thyroid UK

RT3 is an exotic test and i wouldn't know what to do with results

Have you ever heard anything so stupid coming out of a drs mouth if you have add them to this post so we can have a laugh. So mad this morning at the gp iv just had a tt bout 10 weeks ago for graves, bloods results were tsh <.001 ft4 20 ft3 3.7 this morning dont have ranges. I wanted gp to do a cortisol and rt3 to sort conversion out and an antibody test to see if that is cosing tsh to be suppressed, and he says "RT3 is an exotic test and i wouldn't know what to do with results anyway you will have to speak to endo" Whats really annoying i have bin with the same dr since my graves and he aint done any research to improve his knowledge on graves. Its like a mechanic bin given the chance to work on a rare exotic car which there is only 17000 (males with Graves) and not getting excited and doing a bit of research so they no where to start. So im going to look for a new dr practice now any one no one near houghton le spring near sunderland rant over now iv got it out and feel bit better now lol time for meds

9 Replies

At least it was honest.

And few (if any) NHS labs do RT3 tests at all.

Have a look here:



i thought rt3 test was needed to see how much is available for cells ft3 (some equation cant remember sorry have graves) rt3, that's what annoyed me with dr i wanted him to help with getting ft3 and tsh up and sort out tiredness and cognitive problems among other things out.


Interestingly I have had a TT for Graves 35 years ago, and my conversion rate is like yours, about 5.5:1. It seems clear to me that once the thyroid has gone, some T3 is needed to replace the small amount of T3 which was supplied directly by the thyroid. It would be useful to do a rT3 test if only to rule it out as a problem.

There is a VERY good reason why your TSH is so suppressed and that is Graves' disease.

Although this is a study on post-RAI patients, it is equally interesting to those who have had a TT for Graves' because it produces evidence of TSH receptors in the pituitary, which help to regulate TSH production, but where there continues to be Thyroid Stimulating Immunoglobulin (TSI) in the blood, it had the same effect on the TSH receptors as TSH. In other words, the pituitary TSH receptors respond to the TSI the same as it would to TSH. Then it shuts down production of TSH regardless of how much thyroid hormone (T4 and T3) are in the blood. Thus the TSH is suppressed and the doctor thinks you are being overdosed even though you may well be under-dosed. An antibody test for TSI as you rightly surmise would explain why TSH is suppressed.

I know this last bit has nothing whatsoever to do with rT3, but just thought you might be interested.

Marie XX


I have something to add to this. A doctor who sees you have a Cholesterol level of 4.7, reduces your thyroxine by 50mcg and then says there cannot be any connection when your cholesterol is 9.7 eight weeks later!

What DO they do in Medical School?


I asked for my cholesterol to be checked and he said there would be no point as it would be high. Brilliant, no help, no "lets get you sorted" just surrender to all the implications of high Cholesterol. If I ate bacon every day I'd be told to alter my diet, if a change in dose would do the same thing surely they should be doing that!!!


Yes, but eating bacon every day would have very little impact as it's not the cholesterol you eat that's the problem, its how much your body produces and how you metabolise it.(that's the T3 connection).. you don't need to cut cholesterol in fact you might need MORE of it, but you need to USE it for it's intended purpose - making hormones - and that's what they seem to not know, when it's blatantly obvious!!


Sorry! What I meant was my GP is quick to point out the changes that I should be making to improve my health whilst ignoring my symptoms, refusing to test and being unwilling to make changes.


Testing it isn't much point if he isn't going to do anything anyway, or anything he would do would likely make things worse - The point I was making is that even if he did test it, any methods he would suggest would not do you any good.. (likely all he would do is prescribe statins, and that's not a good idea anyway, less so when hypothyroid), when in reality high cholesterol is very often a metabolism problem, (& therefore linked strongly to Thyroid), it's not eating bacon that produces high cholesterol, that's the widely spread myth, strongly perpetuated by drug companies who make money out of statins.

Loads of info out there, eg. but there are many more.

If you really want to test levels, then there are easy test kits out there, not greatly expensive, as well as private testing. The ratio of high and low density lipoproteins is more significant than total overall cholesterol too though.

Your body makes most cholesterol, (sometimes 3 to 4 times as much) diet has far less significance, but the amount you eat will be linked to how much your body will need to make. So if your cholesterol is high, a common reason is that your Hypothyroid condition isn't well enough under control

Unless you have Familial Hypercholesterolaemia, then artificially lowering it is only likely to cause more problem, not less, and leave you short of the cholesterol your body should be using up and getting thyroid well under control is likely to do far more, and the cholesterol will be properly used for it's actually purpose, in making the hormones the body needs. If your levels are high and thyroid is truly optimal then there is a host of other options to control it less problematically than anything a Doctor will prescribe.

As an example, my own cholesterol level reduced very significantly (5.2 to 4.6) when I INCREASED my fat intake (and that was a LOT more than I ever ate previously!) by eating a low carb diet.


Get drunk it appears! :-(


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