Reverse T3 tests

[AliciaM]

I need to get a reverse T3 blood test....will GPs in the UK order these?

[SeasideSusie Remembering]

Alicia

I doubt any GP would know what reverse T3 is! I don't think it's available on the NHS, certainly not at GP level.

Why do you want a rT3 test? Usually testing TSH, FT4 and FT3 gives us a clue.

[Judithdalston]

Why do you think you need Reverse T3 tests- if they are high they will just give a clue something isn't quite right, but not tell you what: chronic disease to acute illness, adrenal/ cortisol problems, low calorie diets, low iron...... etc. A Gp wouldn't order RT3 as won't even do the really important T3 test.

[AliciaM in reply to Judithdalston]

Thanks Judith and SeasideSusie....have been struggling with hypothyroid symptoms for many years diagnosed ME/CFs 2011 and Fibro 2014 prescribed armour thyroid back in 2011...made my symptoms worse. In Italy they found I had a long term asymptomatic Giardia infection and high levels of Epstein Barr. I recovered a little using natural methods but recently my fatigue is back, very weak muscles, now too bad cramps, stiffness and sore joints and have significant weight gain( from a size 10 to a 14 in 18 months) with no change in calorie intake - actually the opposite. My tsh was 1.7 and now 2.5...

Also the weight gain was preceeded by strange letting down sensation in my boobs which lasted several months. My Italian doctor who spoke a little more English than I could Italian was concerned I had a pituitary problem. No help from the endo I saw today.....Reading about the ratio between reverse T3 and Free T3 being of significance as I am considering whether having too much Reverse T3 is my issue?

[SeasideSusie Remembering in reply to AliciaM]

Alicia

What you need first of all is full thyroid panel

TSH

FT4

FT3

Thyroid antibodies

Also useful are

Vit D

B12

Folate

Ferritin

High rT3 can come from an over range FT4 where T4 is converting to rT3 rather than Free T3, and that's often caused by taking too much Levo when treating hypothyroidism, which is why it's important to see your FT4 and FT3 results. High rT3 can come from other causes too, as Judith has mentioned.

[AliciaM in reply to SeasideSusie]

Thank you...all tests you mention are within normal levels ( usually the lower end) and generally have been for the past 13 years even though I have come from almost bed ridden to not quite fully functioning but better within this time...I am familiar with the work of Dr Westin Childs restartmed.com/reverse-t3/ and am aware of the causes. If I could get a reverse t3 test plus ratio with Free T3 I can either exclude or include as causes of my symptoms.

[SeasideSusie Remembering in reply to AliciaM]

Alicia

Why don't you post your latest results for all the tests you have, including the reference ranges, then members can comment. The rT3 test can't be done by your GP and is an expensive test to do privately. We may find something in your test results that gives us a starting point.

[greygoose in reply to AliciaM]

I'm afraid the rT3 ratio is false science. When you read about it, it says 'may show this' and 'could show that', but nobody really knows. The problem is that it's not a true ratio. A ratio has to be calculated with like elements. On the other hand, you have the Free T3, but on the other hand, the rT3 test is a Total test, and contains both Free rT3 and bound rT3. So, you're not comparing like with like. It doesn't mean anything, but some people try and give it a raison d'être that doesn't exist.

You likely know if your FT4 is too high and you're not converting well; if you're on a low-calorie diet; if your ferritin is low; if you have an infection; etc. etc. etc. So, what more could an rT3 test possibly tell you? My personal opinion is, it's a waste of money.

[jimh111]

I would endorse greygoose's comments. Whilst reverse T3 has a role which is poorly understood getting the actual number doesn't help, there is no science to tell you what a particular value means, other than it is high or low. The reverse T3 assay is a specialist test, you wait a long time for the result and it is expensive. Looking at an fT3 / Total rT3 ratio is pseudo science, it implies a precision of understanding we just don't have. quite apart from comparing free with total hormone levels.

rT3 will decline if the patient takes T3 medication and little T4. The benefits are more likely due to bypassing deiodinase mechanisms than altering the fT3 / Total rT3 ratio. You can alter this ratio in the same way by taking too little thyroid hormone (if you are hypothyroid) giving you a 'good' ratio and hypothyroidism.

I'm particulary concerned about Westin Childs marketing 'T3 Conversion Booster'. This is completely dishonest, if only, a supplement that could improve our conversion of T4 to T3 which would need to be specific to type-2 deiodinase since type-1 deiodinase produces reverse T3 as well as T3. This reveals Childs does not understand the subtleties of ddiodinase. Even the name 'T3 Conversion Booster' is incorrect as we would not want to convert our T3 (to T2), we would want to boost T4 conversion.

If you have low normal fT3 and fT4 with a non-elevated TSH it is more likely your pituitary is underperforming and this reduces your T4 to T3 conversion. In this case some T3 supplementation would help. It would be helpful if you could post some TSH, fT3, fT4 results along with details of any thyroid hormone doses.

[Judithdalston]

You have answered some potential problems yourself- same treatment for 13 years, increasing TSH, tests in the lower end of ranges. I have hypothyroidism, fibromyalgia (and diabetes) and gone down DIY route of improving my FT3-which certainly has helped very disabilitating symptoms. As SeasideSusie says get all those blood tests done, then post here for advice.