Thyroid UK
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Latest blood results including RT3.Need help!!!

Following my previous post I have now written out the results.  I understand the photo wasn't clear. Here are the results and I desperately need help working out the rt3/t3 ratio.

Also any comments on actual thyroid results now.

Total T4 90(58-161nmol/L)

TSH 0.01(0.40-400mlU/L)

Ft4 15.3(11.5-22.7pmol/L

Ft3 5.7 (2.8-6.5pmol/L

Ft4:Ft3 ratio 2.7(2.0-4.5 ratio)

RT3 0.31 (0.14-0.54nmol/L)

I don't understand how to work out the RT3/t3 ratio which I am.told is important. 

19 Replies


Thyroid levels look great.  TSH is suppressed, FT4 mid-range and FT3 in the upper third of range.

I don't know why the rT3:T3 ratio is supposed to be important or how you can calculate it.  rT3 isn't high which is the main thing.

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Thank yoy Clutter 

Keep reading about the ratio of RT3/t3 being important.

Some say 11 and some say needs to be near 20. But difficult to work out when measured in different units.

I am still getting the hard heartbeat and the sttm website say high RT3 can cause hard heartbeat that's why I paid all this money to get RT3 ratio.  

A hard heartbeat isn't a sign oovermedication is it? It's a fast heartbeat that indicates that isn't it?

I remember you once said sometimes symptoms lag behind once you've got good levels.

Can this be the case?



Symptoms can lag behind good biochemistry by a couple of months and maybe longer for some people.

Your rT3 is mid-range so you can rule out high rT3 causing hard heartbeat.  If I remember rightly your issue with hard heartbeat was worse in the afternoon and evening and coincided with the times you had high cortisol.

FT4 and FT3 are within range, not even high in range so you are not overmedicated.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

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Yes my hard heartbeat is more noticeable in the afternoon / evening. Trying to get to sleep is really hard.

I've been taking holy basil for the high cortisol and according to DATS my adrenals are happy because temperatures are stable.

I haven't yet done another cortisol test yet though. Im just still taking the holy basil. 

Well I'm glad I'm not overmedicated so that's Obe good thing.

Do you think I should make any adjustment to my doses or leave things as they are now and see if this heartbeat thing settles down? 

Thanks again Clutter 



Unless you have obviously hypothyroid symptoms I would stay with your current doses.  FT3 top of range can make some people feel over medicated.


Thank you again Clutter.

I have no obvious hypo symptoms but then again, I don't think I've ever in 30 years ever had hypo symptoms like what I read about 

I've never had fatigue, weight gain, suffered cold,  lack of sweating. In fact I have always been totally opposite....  Slim size 10. Lead a very active life. Sweat profusely especially in the summer.

My tsh always ran about 2.45 on levo only for most of the years I've been hypo. 

So you reckon I stay as I am. 



Yes, I would, raising dose might increase heat intolerance and sweating.



Clutter given good advice re results.

Calculating RT3/T3 has a simple equation but is actually multifactorial and immensely complicated. The result will depend where your FT3 result lies within the given range as over (or under) medication of T3 in the first place will distort the result.

I read the ratio should be about 1:20 but have never used it or heard of a UK endo using this protocol for prescribing treatment.

(Excess) RT3 is a dysfunctional response designed as an essential brake to too much T3 or when meds aren't working properly, and a high result will block cell receptors to T3 creating a further low. Low T3 can create further RT3 by a malfunction of the diodinases which also relies heavily on good nutrients, iron and cortisol levels. Also by extreme dieting (increased to slow the metabolism and make better use of the available food). 

A fast heartbeat can be overmedication of thyroid meds, high cortisol, high RT3 (as in my case along with jumps and bumps and "normal results") when meds just aren't suited for a variety of reasons, or even low ferritin. Blood pressure lows together with hypothyroid symptoms indicate struggling adrenals.

I would suggest assessing the whole picture and starting with optimal nutrients, iron and then cortisol levels.


Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.



Hi Flower

Are you able to interpret my results regarding RT3/t3 ratio as you seem to know how to figure it out?

I've done the cortisol tests via saliva and treating accordingly. At the moment things are stable in thadept according to DATS.



No I haven't done this but the equation is in the links I have given.

I wouldn't recommend this path without a practitioner who is familiar with RT3 as consider the variables too great to confirm a definite result. 


High cortisol (hard heartbeats in the pm) will interfere with the thyroid function decreasing TSH, lowering thyroid production, inhibiting T4-T3 conversion & increasing T4-RT3 conversion. 

It may also interfere with blood sugar levels and wake you between 2 & 4am every morning.

I would say HARD heartbeats may be that your meds aren't suited due to deficiencies in either Vit B12, Vit D folate or ferritin. Are you definitely optimal in all these? 

A deficiency in any of these will decrease thyroid function so compromising adrenals and causing high cortisol ? ? ? ...


I have tested optimal in folate ferritin vit D B12. 

I had high cortisol but have addressed that with holy basil and I have done several DATS which suggest adrenals are now happy as they are stable.

So basically I'm no further forward.

Clutter has said my thyroid levels look pretty good now.

What do you mean by my meds may be unsuited to me??

Many thanks 



Some people have only a small margin to make their thyroid meds work for them. If something is out of kilter (ie low B12, etc) it can set a whole catalogue of events off that eventually stop meds working. This is one reason why many feel well when initally starting meds only to go down hill several weeks later.

If you have optimal nutrients & iron, thyroid antibodies are controlled (if you have any) and eat a healthy g/f diet with 3 meals a day (so there is no inflammation in the body) and cortisol is adequate, then it would be time to look at changing meds as not every med suits all.

If you have high cortisol levels that could be your achilles heel (at this moment in time) and I have the same problem. Anxiety and stress causes poor adrenal function, whether it is physical, emotional, psychological, environmental or illness. I take Nutri Advanced Siberian Ginseng & Liquorice but Holy Basil is proven to be excellent at regulating// reducing cortisol too.

Adrenals love Vitamin C & I take up to 3g daily. If taking large amounts of Vit C upsets your tummy, try calcium ascorbate which is a gentle non-acidic form. However be aware that the calcium amount should be factored into your over all daily total.

Often taking a supplement isn't enough so we have cut any negativities out of our lives and focus on keeping life calm. I have always practised yoga and meditation but now make it a daily ritual. Sleep is very important but can be disturbed with adrenal problems as can blood sugar levels (more bodily stress) so it is vital to eliminate sugar and any high carb foods to keep an even insulin secretion.

Remember not only thyroid meds take time to work but symptoms can lag behind good biochemistry and cortisol issues can take many months//years to resolve. It has (probably) taken years to get us into this state so may take a while to get us out. Don't be down hearted as you are on the road to recovery - just (possibly) a slow one.

You are asked on the TUK website not to phone re test results as admin staff are unable to interpret. Clutter has given you advice re Dr Alyssa Burns-Hill to discuss interpretation of your test result & as there is (obviously) a consultation fee involved,  I feel it would be prudent to ask whether she uses the RT3/T3 ratio in her assessment.


Disclaimer: I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


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Thank you for all that info.

Dr Burns-hill charges £95,00 to discuss results done through Genova via thyroid UK. 

Unfortunately that on top of the £146,00 for the blood tests is out of reach for me. So basically having the test done has been money down the drain.

Very disillusioned 


I don't have a practitioner to work with. I got these tests from Genova Diagnostics through Thyroid UK.

But I'm now told by Genova thst Thyroid UK is my practitioner.  I've tried calling them today but no answer and no voicemail.

So it seems I've wasted a whole lot of money yet again .



Thyroid UK are your practitioner only in the sense they receive your results from Genova and forward them on to you. Thyroid UK can't interpret your results but you can pay for a consultation with Dr. Alyssa Burns-Hill if you want an interpretation and recommendations.

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The FT3/rT3 ratio is awkward to calculate because different countries and labs have different units of measurement. The STTM calculator works with some units of measurement and not others.

In the case of your results and units I think the calculation is simply :

Free T3 divided by Reverse T3 = 18.4

So, on the basis that people claim the ideal to have is 20 or over, (on what basis I don't know) then yours is really not too bad. You either need a tiny bit more Free T3 or a tiny bit less reverse T3 to make it 20 or more.

I don't know what you take for treatment. If you add more T4 (either in levo or NDT) to your meds there is a chance it may have little impact on your Free T3 and may just increase your Reverse T3. But you'd need to try it and see if you felt it was necessary.

If you have high cortisol I would personally suggest working on that first. If you can get it into a healthy range then your reverse T3 may reduce.


Thank you humanbean for your reply.

I managed to work out the ratio by using the sttm calculator and got the same answer as you 18.4 so thank you for going to the trouble of working it out for Mr.

I did have high cortisol on two points which I've been addressing with holy basil. 

I've done two sets of DATS and testosterone was stable..

I've since reduced one of the doses and now only take 2 holy basil an hour before my bedtime high. 

I am now doing a 3rd set of DATS to see if my temperature is still stable. 

At the moment my dosing is as follows:-

Morning 100mcgs t4 plus 15mcgs t3

Afternoon approx 2pm I take 10mcgs t3.

Based on this and my results both general thyroid result and RT3 result, what would you suggest I do?

Is this RT3 level really important? 

Thank you so much for your help 


Thank you very much.

I've worked out my ratio as well and your calculations are correct.

My rt3 at 0.31 is apparently high.... According to thyroid Advocates it should be 0.17 so how would I go about sorting that out pkease?

I'm addressing high cortisol with holy basil.  I've done three sets if DATS over time. Each time I've changed doses I've done DATS after 5 days. So far I'm getting stable DATS and average temp fir the 5 days was 36.9.

Thank you so much for your reply 


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