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Thyroid UK
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Need help please understanding blood results

Hi everyone. Not posted before so hope it’s ok to ask. I really want to feel better & hope someone can look at my thyroid results and advise.

TSH is <0.05 mIU/L. Range 0.4-5.0 Flag A

Free T4 is 20 pmol/L. Range 9-19 Flag R

Free T3 is 3.4 pmol/L. Range 2.6-5.7

Nutritionist told me that free T3 is in range but said it’s the ratio between them that’s important? And T4/T3 ratio is too high at 5.88. Can anyone help me understand what this implies and what I can do about it.

I’ve been hypothyroid since thyroidectomy 40 years ago. I also have other conditions that are unstable, including Addison’s disease and ulcerative colitis and others. I don’t absorb meds well due to the gut disease. I’m just so completely exhausted all the time and have low bp and heart rate. I think that the Addison’s is also causing some of this as I have trouble getting enough meds on board for that. But I just never feel well these days.

Despite so many of my other blood tests and this being flagged up as abnormal, contact patient or further tests required, I am being told they are all ok. Even my Vitamin D which came back at 35nmol was ‘normal’. Nutritionist suggested a supplement and it has risen to 103.

I hope you guys can help me understand if there is something I can do to improve things.

Thanks so much.

27 Replies

Your TSH is well below the bottom of the range. But, as you are on thyroid hormone replacement, it really doesn't matter.

Your FT4 is highish, slightly over range, but that's not terribly important, either.

What is important is that your FT3 is too low. That's why your T4/T3 ratio is wrong. But that doesn't matter very much, either.

The real problem is that you are not converting your T4 (a storage hormone, levo) to the active hormone, T3. So, not only is your T3 too low, but you also have a lot of unconverted T4 in your blood, which could convert to too much rT3, with the complications that that can cause.

In an ideal world, doctors would look at your results, and understand the problem, then reduce your levo a little, and add in some T3. In this world, your doctor doesn't seem to realise the implications of your skewed T4 to T3 ratio, and will probably do nothing.

There's not a lot you can do yourself, except buy your own T3, and self-treat - or try and explain things to your doctor in the hope of getting through to her, and hope she'll prescribe it, but that looks less and less likely, these days.

Have you also had your vit B2, folate and ferritin tested? Because if your vit D is low, they could be, too. And that could have something to do with your conversion problem.


Thanks for your helpful reply. I haven't had those tested since April. The results then were:

Folate 5.7 ug/L range 4.8-19

Ferritin 33ug/L range 5.0-204

B12 701ng/L range 189-883

I do take B vitamins as a supplement but Dr stopped my Folic acid which I had needed for several years as it was constantly low.

Hope that the doctor will help me with T3 and would like to reduce the levo too.


You can buy your own folate, you don't need your doctor's permission. But, get methylfolate, it's better than folic acid. Your folate is rather low.

OH! And your ferritin is low, too. You really should be supplementing that.


Thank you, that's a great help. Do I buy that and ferritin from the Chemist?


I think you would be better off getting supplements from Amazon, as so many of us do. There's a better choice, better prices, and no pharmacist demanding to know why we want them!


Hi Lindaanneb Of course it's alright to ask questions :)

I see you had a thyroidectomy so presumably you are on thyroid hormone replacement. What are you taking and what dose? I would guess, by your results, you are on Levothyroxine only. You say your gut disease means you don't absorb meds very well. Are you on a very high dose of Levo? If not then it does look as though you are absorbing your Levo OK, perhaps you can clarify.

About the T4:T3 ratio. Good conversion takes place when the ratio is 4:1 or below, so your nutritionist is right when he says yours at 5.88 : 1 is too high. You get the ratio by diving T4 by T3 so 20÷3.4 = 5.88.

So, what do you do about it? Well, look at your results:

FT4 - 20 (9-19)

FT3 - 3.4 (2.6-5.7)

Your FT4 is over range and your FT3 is right at the bottom of it's range. So you've got lots of T4 sloshing around which isn't getting converted to T3, and it is T3 that is the active hormone, the important one that does all the work.

Why isn't your T4 converting to T3? First of all, vitamins and minerals need to be at optimal levels for thyroid hormone to work properly, be that synthetic hormone or our own. What tests have you had done besides Vit D? Have you had b12, ferritin and folate tested? If so what were the results (with reference ranges)?

Vit D is recommended to be between 100-150, ferritin half way through range (with an absolute minimum of 70 for thyroid hormone to work) folate at least half way through range, and B12 at the very top of range, even 900-1000.

Supplementing with selenium helps conversion of T4 to T3.

Whatever meds you are on, if you can get your vits and mins at optimal levels that might help but as your FT3 is so low I would suggest that you need the addition of T3, or if you already take it then an increase is needed. It might be that you need T3 only.

I imagine your Addison's and Ulcerative Colitis impacts in some way regarding your overall, and possibly, thyroid health but I don't know enough about them to comment. My late hubby had UC and I remember he was on lots of meds.

A quick Google shows

"People with ulcerative colitis may have problems absorbing folate (also known as folic acid or vitamin B 9) and other B vitamins, especially vitamin B12."

And that iron, Vit D, calcium and B vits are deficiencies to look out for. Basically what we always advise to get checked.

There's also recommendations for supplementing with Omega 3 fatty acids, turmeric and probiotics. Hopefully your nutritionist has looked into and advised about supplements regarding your UC. What's being done about your Addison's?

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Thanks for your help. I take 125mcg Levothyroxine. Previous to my Addison's diagnosis I took 175mcg Levo which was then reduced. They also stopped my folic acid, prescribed by the Gastro Dr. It had been constantly low before that. I just take Mesalazine PR for the gut inflammation and it doesn't control it enough. Had to stop Azathioprine as it damaged my liver.

The nutritionist I recently started seeing is giving me several anti inflammatory supplements and also omega 3 so that's positive.

I take steroids for the Addison's. Hydrocortisone 50mg and Fludrocortisone 200mcg (renin still high implying it's still not enough) .

Yes you are right. I must be absorbing thyroxine well to fill me up with excess T4. Day curve test have shown I don't metabolise the steroids as needed, with cortisol not rising quick enough or high enough. If I inject my hydrocortisone it's better but that is just for emergency. I'm just not sure which problem is causing the low everything symptoms I'm getting but feel it is probably the thyroid imbalance as adjusting the Addison's side of it doesn't help.

I need to talk to the doctor and hope she will help me with T3


Looking at fT4/fT3 ratios is not really valid, it depends on the individual fT3 and fT4 values. If fT4 is high you can produce something called 'reverse T3' (rT3) which blocks the action of the active hormone T3. If both fT3 and fT4 are low but the ratio is good you are still stumped. So I'd forget about the ratio.

Your fT4 is a bit too high. Your fT3 is low. The TSH is rather low and in most patients it would indicate a little overtreatment. Given your case history and signs of hypothyroidism it makes sense to pay more attention to your symptoms that the TSH. I would suggest you ask your doctor to replace 25 mcg of your levothyroxine with 10 mcg liothyronine (the tablets are 20 mcg so split them into quarters and take one quarter before breakfast and at night). Liothyronine is much better absorbed than levothyroxine. If you find this too much perhaps reduce your levothyroxine a little more for a while.

Many patients without a thyroid find they need NDT (thyroid extract from pigs) but it is very difficult (almost impossible) to get a prescription for this so try the liothronine route first.

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Ah jim! So glad to hear someone else say that! I've never thought the T4/T3 ratio had much use. :)


Thank you. That really clarifies things. I think armed with this info I will feel more confident asking the Doctor for help.

I wonder if it's a good idea to reduce the levothyroxine a little anyway so I don't have so much excess in my blood. Does it work that way? My symptoms are all low. Low BP, low heart rate, slow palpitations, no energy. My Endo had to wake me up in the waiting room to go in for my appointment. He did on that day increase my Fludrocortisone for Addison's which should raise BP and all these things and it did a little but nothing changed much. My Renin is still high which implies it needs increasing more. Then if I can get the T3 added in it sounds like I could feel a lot better, thanks.


Have you had your thyroid antibodies tested? Some of your gut issues could be down to Hashimotos thyroditis.

Do you avoid certain foods with your colitis?


The OP doesn't have a thyroid, so she won't have Hashi's antibodies. :)


Ahh good point! I missed that info.

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That's interesting though. I don't think I've ever had thyroid antibodies tested. Maybe that's why with no thyroid? I want to learn as much as poss about all this so I feel better equipped asking for the help I need. I asked my Endo for a print off of my test results and he said there was no point as I wouldn't understand them!

Yes I'm very food sensitive. Can't take wheat/gluten, dairy, other grains, strong foods etc. I've started food supplements now that I hope will help with all of this.

Thank you.


Get a copy anyway, it's your right they are yours! Then post on here as there's lots of people who will understand them. Odd reply from him.

Research leaky gut. Kris Kresser website is very good.

The Immune system recovery plan by Susan Blum is very informative and easy to understand. Really recommended it.

I'm really good sensitive too, almost a new find every day!

Wheat, grains, gluten, most dairy, potato, tomato and chilli....

Humph, it's not fun is it?! I was such a foodie too.

Hope you start to feel better soon.


That's great thanks, will look into those. Also will post any results I get. I have learnt such a lot from these replies and fantastic help.

Oh dear! same as me. I can't eat any of those either but what we do eat must be healthy as that's all that's left. I love food!


Exactly! How healthy we are going to be when we've cracked it!

Good luck. Post anything new you learn.



I've been drinking a bit of a bizarre concoction in the mornings which seems to be helping my gut and also meant to be good for adrenalsz

Two tsp apple cider vinegar, 1/2 tsp cinnamon, tumeric and 1/4 tsp cayenne pepper in a tumbler of water.

Horrid but helping.

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Sounds a good but revolting mixture but will give it a try, thanks


Am wondering what steps you are able to take with regards to healing the gut. I have had Crohns for over 40 years and have been gluten free for 4. Of course it does not work for everyone but it can be one way of reducing inflammation.

Hope you soon feel stronger ...


Thank you. That does make sense. Have you found it helps you a lot to avoid gluten and brought down your inflammation? I am very food sensitive too. When I stopped wheat/gluten and dairy I did see an improvement so have been off those for several years now but it didn't solve it and had to take out other foods as time went by. Since I started seeing a nutritionist this summer she put me on what must be an exclusion diet and I have seen a big difference. Still have high inflammation and not in remission yet but a big improvement. Also now taking supplements along with meds which I'm hoping will give back some control. It's hard to balance these problems sometimes though when they work against each other. Best wishes.


Being gluten free has reduced thyroid anti-bodies down to around 300. They were in the 1000's. I read the book by Datis Kharrazian - Why Isnt My Brain Working - which convinced me that gluten was not a good idea 😯

If your T3 has been low for 40 years then it would seem the cause of your adrenal issues. I think you should have T3 added. Paul Robinson has a website ....


He talks about T3 and adrenals in his book and lots of good information on his website.

Hope you soon feel stronger.


You did not say what dose of levo you are on. It appears you are on too much. If I pushed my FT4 up that high, I would be an anxious, nervous wreck! How does your levo dose compare to the Abbott recommendation of 1.7mcg/kg body weight? Your FT3 is only 25% up into its range, so your conversion is insufficient. If I were in your position, I would reduce levo and add T3. If you don't think you can do this by feel and want to use testing, then I would be inclined to reduce levo until FT4 is about mid-range, then start adding T3 in small increments, ~5mcg, every 4 days. If you start feeling hyper, you can always dump T3 for a day, then regroup at a lower dose of levo if need be. You probably want to aim for a T3:T4 dose ratio somewhere between 1:4 (NDT) and 1:10. I am at 1:5.

I am not bothered by TSH under the usual lab range. However due to meta-analyses I have read that claim TSH less than 0.04 *might* have negative consequences, I am not inclined to push it as low as yours. Your response to low TSH might not be the same as mine, however, I cannot recall that I have ever felt well when I have pushed TSH<0.1. YMMV!

What are you on for Addison's? I have heard that many endos put patients on prednisone. That makes me nervous, since it is hardly bioidentical to hydrocortisone. What are you doing (if anything) about DHEA level, which is likely low?


Thank you for your help. I'm on 125mcg Levothyroxine. Interested to do the sum and see that is spot on for my weight. My Endo says he is reluctant to reduce it because I'm so fatigued and all the other low symptoms. I am the opposite of anxious or nervous, almost inert.

Now I'm learning all this I doubt that's in my best interest to just continue as now. I wonder then if I would feel better just from reducing the thyroxine a bit anyway until I can sort some T3 help from my doctor or elsewhere.

No I'm not on prednisone for the Addison's. I take 50mg Hydrocortisone and 200mcg Fludrocortisone. Both above average but still too low for me. My doctor wants to add in a small dose of pred to help me stay ok through the night. Hoping that will help.

Frustrated with the lack of help with DHEA which I am sure is low. I only get my life saving hormones replaced not the ones that enable you to live it. I have complete adrenal failure so don't have any residual function now. But if I can improve the thyroid situation I'm sure it could make a huge difference.

Many thanks


If you can't get help with T3, you can treat yourself. Some members of this board buy T3 from the internet. I can give you site suggestions if you want to go that route. Yes, it is maddening that docs have this nasty habit of doing the minimum necessary to keep people alive, but won't give them what they need to be well. My suspicion is that pushing your FT3 into upper half of its range, and pushing your DHEA to that of a 30-something female, would help pull you out of the dumps ... assuming you are doing all the nutritional supplementation that is suggested here.


I would certainly bring your t4 dose down and add a little t3 as suggested. It may be that you need a boost with t3 to get your heart rate slightly higher and blood pressure normal. However some people just do have low blood pressure nomatter what. I always do. I often get told it's nice and low but along side that is tiredness, getting out of breath easily and at times becomming light headed so I don't think it's all that good. Also try and get all those vitamins up. You can get sprays now which are great so don't irritate your gut as much as they are absorbed quickly in the mouth. Good luck.


I will do that, thank you. I'm feeling optimistic now about getting this balanced. Will look into the sprays as well. I have learned so much today


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