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T4:T3 ratio test results

T4:T3 ratio test results

I hope someone can help me interpret the above results which I've just received (Genova END08 urine test for T4 and T3 and conversion).

To put this into context, I have never been diagnosed with hypothyroidism despite being symptomatic and my TFTs are always in range (please see profile for info).

I have, however, been diagnosed with mitochondrial dysfunction and low nutritional status (despite a good diet), especially magnesium and folate, all identified through Acumen CFS profile testing. Currently taking supplements.

My naturopath is recommending I take Thyro gold (given it is impossible to source Nutri thyroid), but I am hesitant given my euthyroid status.

The ratio T4:T3 looks perfect (1.14), but the actual measurements (especially the T4) seem a little low though in range. The results are below.

I would be grateful for any enlightenment.

With thanks, Ann

22 Replies

Ann - Dr Peatfield, in his book 'Your Thyroid and How To Keep It Healthy' discusses the urine test as follows:

"...24 hour urine test, where a sample of urine collected over 24 hours is measured for T4 and T3. This test shows the T3 and T4 which has been used in 24 hours, rather than what is present in the bloodstream, where a good proportion may not have been properly used..... This is therefore a good deal more sensitive than the standard tests, although convincing doctors may be another matter."

Apparently, also, as this is a more sensitive test it can be useful in picking up subclinical hypothyroidism that may be missed (according to Genova Diagnositics). It would seem that the urine test can pick up the milder cases of hypothyroidism whereas blood tests tend to pick up the more severe cases (according to The European Laboratory of Nutrients).

So the urine test is showing what has reached the tissues during the time of collection. Yours shows that not much T4 is but what does is converting well enough at the moment (suprisingly!). One would expect to see both T3 and T4 in balance, probably nearer to or to the right of centre on the scale.

Do you have any current thyroid blood tests? Just wondering what they look like.


The latest TFTs were done by Blue Horizon in March 2016:

TSH 2.38 (0.27-4.20)

Free T4 15.59 (12-22)

T4 total 92.7 (64.5-142)

Free T3 4.17 (3.1-6.8)

Reverse T3 18 (10-24)

Antithyroidperoxidase 12.2 <34

Antithyroglobulin 10 <115

Folate 10.9 (10.4-42.4)

B12 621 deficient <140

Ferritin 109.8 (20-150)

(no T3 done, which is frustrating)

The latest NHS results were in Dec 2016:

TSH 3.12 (0.27-4.2)

B12 1158 (191-663) (always high)

Folate 16.8 (3.9-26.8) (this has increased from 5.8 (4.6-18.7) in 2015 due to B12/Folate supplementation; hence also the rise in B12)

MCV 89.1 (80-100)

Vit D 98 nmol (>50)


Ann - In March 2016

TSH 2.38 (0.27-4.20)

Free T4 15.59 (12-22)

T4 total 92.7 (64.5-142)

Free T3 4.17 (3.1-6.8)

These show that your thyroid is struggling. Your TSH is a bit higher than where a healthy person's usually would be (that would be probably no more than 2). Once it reaches 3 in some countries you'd be diagnosed hypothyroid. FT4 is 35% through it's range and FT3 is 28% through it's range. Both are below what you'd expect to see in a normal healthy person, which I believe would be about half way (possibly more). Of course, we're all individuals so nothing is set in stone. Some people might find your results are perfect for them.

In December 2016

TSH 3.12 (0.27-4.2) - your TSH is rising (good that the range is the same) - a sign of hypothyroidism and with that result, as mentioned, in some countries you would have had a diagnosis of hypothyroidism.

Vits and mins seem fine at that test.

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I Cannot answer your question but researchers have found that a 3:1 basis was best (T4:T3). I shall give you a link and go to page 80 and read the top para on the left-hand side.


Thank you Shaws - if you see the exchange of messages between SeasideSusie and me (below) there seems to be a mistake with the calculation as Genova have done a T3:T4 ratio calculation, not T4:T3 (and this is the same with the sample report on the website).

It isn't giving me much confidence :-(


With that ratio, my T3 should be 3.63, but at 1.38 it is lower than the T4! Not sure what that means.


Which results are you talking about here Ann?

The urine test T4:T3 ratio is 1.21 divided by 1.38 = 0.87

With your blood test the FreeT4:FreeT3 ratio is 15.59 divided by 4.17 = 3.73

You can't compare urine and blood tests, it doesn't work as they measure different things.


I was referring to the urine tests and I've made an error. If the T4:T3 ratio is 3:1, then my T3 should be 0.4 as the T4 is 1.21.

But there is still confusion - as you state below, your tests are testing T3:T4 ratio but the Genova website says that the test is for T4:T3.

The document Shaws has posted above is referring to T4:T3 also.


The document Shaws has referred to is talking about the dose of Levo (T4) in relation to the dose of T3 taken, it's nothing to do with the ratio of FT4 and FT3 in test results

"Dose Selection in T3/T4 Study RCTs

The second logical basis for a conclusion is the actions taken, i.e., the doses given to the subjects. Most subjects received T3 below its adult starting dose of 25 mcg/day.23 The subjects in RCTs received T3 in some ratio to the withdrawn T4. The various RCTs used T4:T3 ratios of 14:1, 10:1, and 5:1. Subsequent research by the US National Institutes of Health (NIH) found the therapeutic equivalence was 3:1.41 Thus, most of the subjects were under treated with the T3/T4 combination. In light of the NIH finding, the conclusion that T3 therapy is never needed is invalid."

They are saying that a Levo/T3 ratio of 3:1 was better.

So where you say

If the T4:T3 ratio is 3:1, then my T3 should be 0.4 as the T4 is 1.21.

this isn't relevant. You need to separate ratio used in blood tests from the ratio used to dose Levo/T3, they're just not the same.

And the ratio of FT4:FT3 in blood tests are probably not comparable to the ratio of T3:T4 in urine tests.

The fact that in blood tests the FT4:FT3 ratio should be 4:1 or less (some say 3:1) is nothing to do with the dose ratio of 3:1 that is mentioned in the document linked to.

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Thank you for the explanation - obviously something has been lost in translation!


OH, I'm glad you understood that, I had to read it a couple of times :D

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Ann - PS

You have put T4:T3 looks perfect (1.14) whereas the test result actually shows T3:T4 ratio which is worked out by dividing the T3 result by T4 result ie 1.38 divided by 1.21 = 1.14

The T4:T3 ratio is 1.21 divided by 1.38 = 0.87

I don't know what a perfect ratio is with a urine test, but with a blood test the T4:T3 ratio should be 4:1 or less and I've seen it said 3:1


I'm now very confused as on the website ( it says the test is to measure T4:T3 ratio, but in my report and

the sample report ( it is giving the T3:T4 ratio, so the wrong way round!

This is alarming and very worrying!

I have already had to query their information as on the form they sent with the test kit it stated that the test was for identifying FT4 and FT3 and there was no mention of the conversion/ratio (we exchanged messages about that a couple of weeks ago).

Also, the ratio range isn't given on my report (it is on the sample) so I'm awaiting a call from the practitioner who received the results. I'll also ask about the way they have worked out the ratio.

I'll let you know the outcome.

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Ann - I believe it is the T3:T4 ratio. I have done this test a few times and I've just got my results sheets out and hey all say T3:T4. I see that they now show the ranges as nmol/24h rather than pmol/24h. It makes no difference, it just shifts the decimal point two places to the left, ie pmol/24h was T3 - 610-3380 and it's now nmol/24h - 0.61-3.38.

However, I note there is no range beside the T3:T4 ratio any more. The range on all my tests is shown as 0.50-2.00 and anything under 0.5 was marked as LOW with a red border around it, anything above 0.50 had a green border around it. So it would be good if you could also ask them about a range for the T3:T4 ratio, use my old tests as an example if you like.

I have to say, I'm beginning to lose faith in Genova a bit. Besides the discrepancies you've experienced, I've read about their saliva adrenal test having new ranges and I don't think there's been a satisfactory answer to that as people don't seem to be able to compare previous tests with the old ranges to the new ones, I think the unit of measurement is the same so it doesn't make a lot of sense. I don't suggest the Genova adrenal test any more.

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Genova response:

The test *is* for T3:T4 ratio (as well as T3 and T4 values) so they acknowledge that the web page is misleading.

They have stopped providing the ratio ref range as it isn't substantiated by the literature (begging the question: what is the point of giving the ratio?).

However, the range they have used in the past for T3:T4 is 0.5-2.

That means that my ratio of 1.14 is within range.


The T4:T3 ratio range is (traditionally) 2-4.5.

That means my T4:T3 ratio of 0.87 is well under range.


What does being under range mean?


Which ratio is testing what?

I really don't know any more!


Like I said, I'm losing faith in Genova :(

The T4:T3 ratio range is (traditionally) 2-4.5.

Which ratio range? Are they saying that is a urine T4:T3 ratio range? If they've never given that ratio how come they have a range for it?

The mind boggles! I really don't understand it. If T4 converts into T3 then you'd expect to see a T4:T3 ratio, and we're used to seeing that in the Free T blood tests. Doing a T3:T4 ratio doesn't make much sense to me. It's a pity Dr Peatfield doesn't go into more detail in his book, it's hard to find good solid evidence from reliable sources.

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Hello SeasideSusie, I've just had a letter from the natropath who, I had hoped, would be able to shed light on the whole conundrum. However, as he isn't conversant with this particular test (preferring serum levels which he thinks yield more stable results), he wouldn't comment on the info in the report (NB I referred myself for the test without consulting with him, which was a little silly in retrospect).

So, we're none the wiser! I'm not sure whether to contact Dr Alyssa Burns-Hill who would have received the test, though that is yet more expense.

I really don't understand how the T3 is higher than the T4, which is pretty low and heading towards sub-range levels.

And the 'T3:T4 ratio or T4:T3 ratio' remains a mystery...

Re: Genova's reference range in relation to T4:T3, I don't know where this comes from. I should have been more persistent in asking questions, but the person I spoke with was encouraging me to talk it through with my practitioner.


Why would Alyssa have received the test? Are you already consulting with her? If not, she is just named as the 'practioner' so we can use Thyroid UK to access tests by Genova. Test results are sent from Genova to Thyroid UK not Alyssa, and it's ThyroidUK who send the results to you.

I think it would be useful to have a new blood test for TSH/FT4/FT3. You have a rising TSH from March 2016 to December 2016. If it is still rising then your FT4 could well be lower than it was in March 2016 and will show your thyroid is struggling. Your body will do it's best to kick out as much FT3 as possible, even when your thyroid is struggling, as it is the active hormone every cell needs. I'm not saying this is correct, it's just a guess, but maybe your urine results is showing more T3 because of that.


Thank you for the clarification about how the system works re: test results. I have mistakenly thought that the results would go to Alyssa as well as to ThyroidUK as a matter of course as she is the named practitioner and then it is up to the individual to follow it up with her (or not).

In any case, I would have to book a consultation in order to discuss the results and interpretation (as per the info on the ThyroidUK webpage: 'Once you have your test results'), which costs £95 for 30 mins.

Yes, you are right that I should be retested for TSH/FT4/FT3 - which probably would have been the most useful thing to have done rather than messing around testing for any conversion issues. Brain not exactly been functioning properly!


In any case, I would have to book a consultation in order to discuss the results and interpretation (as per the info on the ThyroidUK webpage: 'Once you have your test results'), which costs £95 for 30 mins.

No you don't have to, you can if you want your results interpreted but it's not a 'must'. Most tests can be interpreted just by looking at the results and ranges - high, low, out of range, and for any further clarification to be honest posting on the forum is your first port of call - costs nothing, some members have already had those tests done and know how to interpret them, and sometimes know more than 'practioners'.


Check your PMs :)


Many thanks for your message and advice - I've replied and given an overview of the situation. As I've mentioned, I was only thinking of contacting Alyssa because all other lines of enquiry seemed to have petered out (i.e. naturopath and online forum). I fully understand that I don't <have> to go down this route, but I didn't seem to be getting anywhere otherwise.


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