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Thyroid UK
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Thyroid query re: urine and blood

Hi. I wondered if anyone knows why a thyroid urine test that I had done quite a while back shows high T3 and T4 and yet my blood serum tests always show low T3 no matter what dose and combo of thyroid hormones I take. I barely convert T4 and don't tolerate T3 very well and have tried to identify the reasons why I can't tolerate T3 and rectify but to no avail. I've been ill for years. I just read an old post where a lady had blood thyroid done and levels were reasonable and yet her urine thyroid results showed very low T3. Her doc said that the urine results prove she's not converting and getting T3 into cells. What I can't figure out is how my urine levels for thyroid are high and blood not high. I am very sick, bed bound and also have lyme, viruses, suppressed immune, gut issues, disabled - it goes on and on. I'd love to crack this mystery. I wonder if it because my T3 is just going straight through my body and my receptors are not working. Could that be the case and if so, how do I get thyroid receptors to work. I'm emaciated and severely fatigued and need to try and continue fighting as riddled with lyme too. Can hardly eat or put on weight etc. There must be an answere - I've been searching for years - just can't fathom it out. Thanks if anyone knows anything about this.

22 Replies

This is a response from one of our esteemed medical advisors:-

This researcher doesn't think that urinary T4 is equated to FT4 and isn't reliable in diagnosis. Personally I think urinary T4 is a crude estimate compared with direct blood tests. After all there isn't a kidney in the way of the test and one can't assume that the organ's activity doesn't have some sort of distorting effect as a filter.

WM Wiersinga Ned Tijdschr Geneeskd. 2007 Dec 22;151(51):2813-5. [Determining the thyroid hormones T3 and T4 in the urine: an unreliable test for hypothyroidism].


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Thank you Shaws - yes, it is an unusual test and understand the complications - it's very frustrating for me not knowing where to turn, hence the test. I value your input.

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sunrising If you post the results of the tests you are talking about it would make it easier. Also, what thyroid meds are you taking?

The urine and blood tests are testing two different things. The blood test shows what is in your blood at the precise moment it is drawn and measures the free, unbound, hormone in FT4 and FT3 tests.

The urine test shows what T4 and T3 has been used during the 24 hours of collection. It's not useful for diagnosis, just to show what your body has used. If the urine test is showing high T3 then you must be converting or are taking T3.


Thank you Seaside Susie.

My thyroid blood test results were:

TSH.......25 (0.30-4.20)

FT4........6.2 (12-22)

FT3........3.4 (4-6.80)

I had dropped my Levo deliberately as I felt so ill and was trying to raise T3 at the time but couldn't handle it as always. At one time, I was able to take 125 mcg of T4 and convert it but this conversion stopped and I only noticed because I had become so very ill and did a private test (not the results above). I had been ill for a few years before this test and this is why I was trying to increase T3. I had tried to support adrenals that had mixed highs and low and tested other vits and minerals so couldn't work out why I couldn't handle T3. I do have lyme disease that could be messing this up possibly - who knows!!!!!!!

My urine test that was done around the same time was:

FT3 ......... 1960 (592-1850)

FT4............1470 (347-1994)

T3:T4 ratio 1.3

How can I possibly have high results in urine and low in blood. I'm referring especially to the T3 as it is over the range and yet for years, my blood test results always come back with low FT3 regardless of whether I'm taking higher amounts of T4 or lower amounts. I can't seem to handle taking higher doses of T3 either synthetic or natural. I'm so ill, emaciated even though hypo with a load of dire symptoms due to a variety of diseases and wish I could work out why I can't get thyroid meds to work. I have been working on my guts as I have dysbiosis and most likely leaky but every attempt I make doesn't give me any better results with labs or how I feel.

I tried increasing T4 again recently (because I can't tolerate the T3) and got these results:

FT4.......21.8 (12-22)

TSH......0.4 (0.3-4.20)

FT3......3.9 (4-6.8)

Although my T3 is higher here, I still didn't feel any better for the increase (was taking 75 mcg of T4 and alternating to 100 mcg of T4 daily. T3 was just 3 or 4 mcgs per days split.

I'm at a loss as always and wonder how my body can be excreting more thyroid hormone than is in my blood. I can only think that it's running straight through my body and not being used because maybe my receptors have shut down - but I'm just guessing and no expert whatsoever.

Thanks again for responding



How can I possibly have high results in urine and low in blood

Because you're not measuring the same thing, as explained in my previous reply, blood gives a snapshot in time, urine gives a picture of the whole 24 hours so you can't compare blood and urine results.

[Blood measures Free T4 and Free T3, the urine test states it measures T4 and T3 so it's not been established if it is FT4 and FT3 that the urine test measures.]

As an example, when I tested mine originally I was taking 175mcg Levo. My blood test showed

FT4: 28.59 (12-22) - 165% of range

FT3: 5.14 (3.1-6.8) - 55% of range.

My urine test showed

T4: 1590(550-3160) - 39% of range

T3: 691(800-2500)- minus-6.4%.

So you can see the difference there between blood and urine -

FT4 - 165% and T4 39%

Free T3 55% and T3 minus-6.4%

I had high results in blood and much lower results in urine. So you can see there's no way they're measuring the same thing.


You have a lot going on - other illnesses, you mention high/low adrenal results, you haven't said if your vitamins and minerals were at optimal levels (not just in range), gut problems. All those problems will play a part in why thyroid hormone isn't working for you, sex hormones are also involved (adrenals/thyroid/sex hormones all connected) but that is just a small part of your problem. There is probably too much involved here for anyone to be able to offer much help. If you're getting nowhere with your doctors, how about a Functional Medicine Doctor.

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Thanks for your reply Seaside Susie. I understand your angle, just my brain finds it hard to comprehend but I see what you are saying. I do need to see a functional medicine doctor if I can find one that I can physically visit (bed bound) or one that does skype etc. That's if I can afford it as my finances have taken a real bashing with all these diseases I have. I appreciate your help.



Are you getting any treatment for Lyme as I am sure this will have a great impact on why your thyroid meds, are not working.

There use to be a member on this forum called rosetrees who found out she had Lyme, she was getting treatment for it and was very knowledgeble about it all. I have not seen her on her for a while but I believe she is quite active on facbook using the same name.

If you are on facebook, have a look at the Lyme groups on there and you may find her or find some help from other members on the groups.

I am only aware of this as I thought my daughter had Lyme but thankfully her test came back clear.

I do hope you can find the help you need.

Good luck.

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Thank you for your reply Lucylocks. I am a member of a couple of lyme forums but haven't seen the name Rosetrees appear - she must be in another group. I will look out for her though thanks. I'm bed bound and can't travel so I'm trying to self treat lyme with herbs. I've had so many consultations either by phone, skype or face-tface when I can cope with a visit but not found improvements. I appear to be very complicated with so many issues that are not responding to protocols. I'm thousands of pounds down and still no better. I just have to keep searching and fighting. There are no lyme docs in the UK that effectively treat. Most people go to the USA if self treating doesn't work. Thank you again


rosetrees is still a member here, hopefully she'll get a notification that she's been mentioned :)

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Thank you. Actually, I'm wondering if I do know Rosetrees - it seems familiar now. Not sure though as on Facebook, I don't recall this name but I've seen it somewhere - maybe, it was here. It could be someone I'm thinking of but I could be mixed up - if it is the person I'm thinking of then I would have communicated with her before. We'll just wait and see and thank you again for your help


Hi SeasieSusie,

by highlighting rosetrees name does it mean she will get a notification. Can you please let me know how I do it for future reference.

Many thanks.


Hi Lucylocks

Yes, Rosetrees will get an email notifying her that she has been mentioned.

When you want to do that, you put @ in front of the person's user name but no space. A list of suggestions will pop up (scroll down a bit if you don't see it) then you click on the name of the member you want to tag, it will highlight it blue in your message like lucylocks


Many thanks SeasideSusie, that's really handy to know.


I see SeasideSusie has replied about rosetrees and I think by highlighting her name it means she will get a notification, I should have done that in my reply to you but not sure how to do it. Hopefully she will get back to you.

Good luck.


Thank you


Have you tried T3 only? I found I was very unwell on levothyroxine and it was only as I reduced it and raised T3 the better I became.

Some are intolerant to levothyroxine.


I feel that the Levo is contributing to my dire symptoms although it is confusing as I have lyme and active viruses too but for a long time now, I can't help but feel that Levo is not good for me. However, when I did try and take T3 only, I failed miserably. I can't seem to tolerate T3 and have gone around in circles for a few years now trying to figure out why and fix the problem (adrenals, vits, minerals etc). I get so despondent as I've been like this and wasting away to nothing for too painfully long. I saw Dr P about 3 years ago or so and tried the T3 only route with him (lovely man) and he advised I take HC although I couldn't tolerate that either. HC is bad for lyme and viruses I've been told so many times on lyme forums so it gets complicated for sure. Wish I could just take T3, find some improvements and then just focus on my other issues. Thank you again


Before clicking the reply button, I meant to ask you Shaws how you felt on Levo? Can you kindly tell me what your symptoms were so I can see if there are any similarities? Thank you


These are some - I also felt incredibly unwell.

I felt much worse on levothyroxine - stiff body, muscle and joint pain. Couldn't comb hair, raise arms, step on pavement . Had severe palpitations which were disabling and an ambulance was called often but no heart problems were found. I eventually figured out a way to calm the palps, sometimes pulse 160mcg+.

I had all the usual heart monitors etc but as

the cardiologist was puzzled and was considering implanting something in heart to monitor when/how palps occurred.

However having had great advice from TUK I stopped levo and switched to NDT and had great improvements but T3 alone removed all symptoms.

It doesn't work for everyone and it is all trial and error. We have to have the options of trialling different ones.


Thanks so much for providing the description Shaws; I appreciate that. I can relate to all of the pain in body but luckily my HR hasn't got that high. I know my heart rate isn't right but not that high. I can fully relate to the stiff body (I feel like I'm made of concrete), muscle and joint pain - mine is extreme to the point that I can barely walk but I have other issues too which makes it all confusing for me. I feel that Levo gives me added bone issues to the problems I already have but it is just a hunch - don't know for sure. I'm going to order a different brand of NDT to what I've tried before and see if that helps. I would like to think I could go the T3 route only but the Lyme disease and other issues I have make it hard for me to monitor how my body is reacting to it.

I'm sorry to hear that you had to suffer such also and pleased that you have found improvements following your own path no doubt. It surely isn't right that these diseases are not understood by NHS and mainstream medicine in general. x


One of the most common ways to help with the conversion of T4 to T3 is selenium . Even with leaky gut and Lyme and some of the other issues that you mention the selenium may still help . I've heard of folks taking anywhere from 200 to 400 mcg selenium per day . Be careful not to take more than that because you can overdo selenium . Another thing that can help is digestive enzymes . I go to a functional doctor here in the US . He has a test that actually measures stomach acid and he finds that many times those with conversion problems don't have the digestive powers to convert . One of the other things that he prescribes for help with leaky gut - it may also help with Lyme - is the antifungal fluconazole. Things are different in the US as far as medicines but fluconazole here is very cheap here . It's considered an old and outdated medicine but I've had it a couple times and it really helps me . Of course adding probiotics helps with leaky gut - and is recommended when taking any sort of antibiotic or antifungal. The other supplement that really helps and I don't quite understand how - but it's zinc .

You do have many issues as do most of us with an autoimmune disorder and/or thyroid disorder . But we all have to start somewhere as Dr. Isabella Wentz mentions often - it's like an onion - layer after layer of disease - any one of them by themselves not so big a deal but layer after layer and we begin to be very sick . Same thing is true in reversing it we have to start somewhere - Removing one layer at a time.

I find also that drinking 8 ounces of water with Braggs vinegar in the morning really helps . It can be any vinegar that's considered alive vinegar that is that includes the mother vinegar . Sometimes I have several glasses in a day and it helps with digestion helps with brain fog helps with energy .

I do hope that you're able to find the answers and not be bed fast really Soon. Hang in there there's something that's got the T-4 T-3 unbalanced. You haven't mentioned if your gluten-free . That's an easy experiment that actually saves money! It seems very clear that you have gut issues it might be worth starting there - give it the good things that can be digested by those of us with thyroid problems and gut issues.

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Thanks for your supportive reply dtate. I do take all the supps you mentioned apart from the Fluconazole. It's a minefield for sure and I'm so confused. Yes; I am gluten free and have been for a long time. I've had so many consults and followed so many protocols that I've lost count, hence my reaching out on forums. It certainly isn't simple for sure. I do value your help and wish that my attemps with all the supps had given me some noticeable benefits. I will continue to take the supps though because I'm sure my body needs them even if I don't notice a difference. Something is stopping ,my thyroid meds from working and I'vbe been around the block a lot of times trying to figure. Hopefully, something will help one day. I could do with having the stomach acid test but wouldn't know how to get that over here as I can't travel = just too weak and sick.


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