Is the reverse T3 test essential?

[sassykate0000]

I'm going to pay privately for some blood tests to check my thyroid. Having the reverse T3 done aswell is really expensive. Do I definitely need this done? Im happy to pay extra but just want to double check. Thanks

[humanbean]

I would say no, it isn't essential, at the stage you are at. There are probably a lot of things you can do to improve your health before deciding you need to spend all that money.

[shaws Administrator]

I agree with humanbean and I know one doctor who thought it wasn't necessary as he said.:-

Dr. Lowe: Some readers will not be familiar with reverse-T3, and I know from experience that many others harbor misconceptions about the molecule. Because of this, I have summarized in the box below what we know about reverse-T3. I've answered your question below the summary.

Conversion of T4 to T3 and Reverse-T3: A Summary

The thyroid gland secretes mostly T4 and very little T3. Most of the T3 that drives cell metabolism is produced by action of the enzyme named 5'-deiodinase, which converts T4 to T3. (We pronounce the "5'-" as "five-prime.") Without this conversion of T4 to T3, cells have too little T3 to maintain normal metabolism; metabolism then slows down. T3, therefore, is the metabolically active thyroid hormone. For the most part, T4 is metabolically inactive. T4 "drives" metabolism only after the deiodinase enzyme converts it to T3.

Another enzyme called 5-deiodinase continually converts some T4 to reverse-T3. Reverse-T3 does not stimulate metabolism. It is produced as a way to help clear some T4 from the body.

Under normal conditions, cells continually convert about 40% of T4 to T3. They convert about 60% of T4 to reverse-T3. Hour-by-hour, conversion of T4 continues with slight shifts in the percentage of T4 converted to T3 and reverse-T3. Under normal conditions, the body eliminates reverse-T3 rapidly. Other enzymes quickly convert reverse-T3 to T2 and T2 to T1, and the body eliminates these molecules within roughly 24-hours. (The process of deiodination in the body is a bit more complicated than I can explain in this short summary.) The point is that the process of deiodination is dynamic and constantly changing, depending on the body's needs'

To read the whole question/answer go to the date March 24, 1999

web.archive.org/web/2010103...

[faith63]

rt3 helped me to determine that i did not convert. I was on t4/t3 combo, so it was the only way for me to know for sure. Mine was on the upper end of the range for 16 months. i had an middle to upper ft4 and mid range free t3, but the rt3 was high. It was determined that even 50 t4 was too much meds, so i switched to t3 only. my rt3 was still high, when my free t4 was at the very bottom of the range. Unfortunately, i have cortisol issues, pituitary issues, too, so still not well

[sassykate0000 in reply to faith63]

Thankyou for your reply & im sorry to hear your unwell. Slightly annoyed I've been told there's 'probably other things I can do at this stage to improve my health' by someone who doesn't know what stage I'm at, how healthy or unhealthy I am, my symptoms or what I've done to help myself already. All the best and thankyou again x

[faith63 in reply to sassykate0000]

who is telling you that other things you can do at this stage? What are they saying. I think i missed something here. oh, the reply above?

It is true though, that high rt3 is caused by something and that something, will keep you ill, even on t3 only.

[sassykate0000 in reply to faith63]

Thankyou x