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Thyroid urine test


can anyone explain these recent test results for me please?

Thyroid hormone 24 Hr urine test.

T3....329...ref range..800-2500.

T4...764.....ref range...550-3160

T3 :T4. Ratio. 0.43....normal range. 0.50-2.00


They bear no resemblance to the blood test results see below taken in August so it's difficult to understand them.

free T3....4.2....ref range...3.1-6.8

Free T4....20.21...ref range....12-22


Thank you.

11 Replies

Not surprising as urine tests for thyroid are very unreliable.


The test was one that DrP suggested and so I hoped that someone could explain them as he is ill at present.


SueHG, I've never seen anyone able to interpret urine results on the forum.


I have had the urine test done. I don't know why it is said to be unreliable so can't comment on that but it was explained to me that it shows how much thyroid hormone is getting through and being utilised by the cells, which the blood tests do not show.

My results were not dissimilar to yours. My ratio was 0.43 (marked low) but my T3 was 691 (in the red zone and marked low) and my T4 1590 about one third of the way into the green zone. Like your blood tests, my FT4 was high (right at top of range) but FT3 5 point something so not really where it should have been in relation to the FT4, and my TSH was suppressed (as it always is).

I was advised that the result of my urine test showed that I was not converting T4 to T3 well enough. I am looking into that and have got some T3 and am experimenting with dose of both Levo and T3 at the moment.



That was a great explanation! I was guessing that but it's good to hear it from someone else who has experienced it. I came off Levo as it was making me ill as it wasn't converting and am now on a natural thyroid supplement and so far am feeling much better, but still have many hypothyroid symptoms



Sue, I'm not an expert and these are just my thoughts. If you are on NDT, I know that blood test results can be different from the results of someone on Levo. If you were on Levo I would be thinking that you might need to add some T3 but I'm not sure if the same applies when taking NDT. I will send you a PM


susie, I've seen that explanation before, but I cannot understand how it shows that. How would urine show how much was in the cells? It doesn't make sense to me.


Hi Greygoose

Like I say, I'm no expert and don't fully understand it so can't really explain it. Does the amount of hormones pee'd out show what has been through the cells? I can't say with any certainty.

I went for the urine testing because my blood results, according to my GP, show I am over medicated with a suppressed TSH and very high FT4 yet FT3 not in the upper quartile of the range, and still I have what appear to be residual hypo symptoms. I suspected poor conversion and the urine test appears to confirm that.

I am still looking into urine tests and so far have found this [from a US site and my UK test did not include Selenium]

"Urinary Thyroid Assessment

The Urinary Thyroid Assessment measures unconjugated non-protein bound triiodothyronine (T3),

unconjugated non-protein bound thyroxine (T4) and selenium in a 24 hour urine collection. There are several reasons why a urinary thyroid assessment may be beneficial:

A specimen collected over a 24 hour period

may better reflect the average thyroid gland

output, since thyroid gland activity varies

through the day.

• Quantities of T3 and T4 in a 24 hour urine are

significantly higher than those found in a spot

serum sample, so levels can be more reliably

measured. Measurement of free T3 and T4 in

serum is inherently difficult.

• Selenium is a cofactor for 5’-deiodinase, the

enzyme required to convert T4 to T3. A low

24 hour urinary selenium level likely correlates

with selenium intake and urinary selenium is

also reflective of supplemental selenium.

As shown in the figure below once the urinary

selenium levels rise above 100 mcg/24

hours, the average symptom score begins

to decline. This trend suggests that patients

who are replete in selenium experience fewer

hypothyroid symptoms.

[Sorry GG, I can't copy and paste the graph]

Laboratory Methodologies

There are several different methodologies

used to measure T3 and T4 in urine (e.g. radio

-immunoassay, liquid chromatography mass

spec). This test employs the radioimmunoassay

method as it is the method that found a strong

correlation between test results and hypothyroid

symptoms, and is the method with more than a

decade’s worth of correlative data.

Note: The Urinary Thyroid Assessment is not

a substitute for serum testing in the diagnosis

of thyroid illness; it is meant to assist clinicians

in the evaluation of patients whose clinical

presentation is not readily explainable by

measurement of serum thyroid parameters

alone. See back page for a discussion of serum

TSH and free T3 and T4 measurements."

Also found a link where Mary Shomon asked the question about whether saliva and urine thyroid tests were accurate thyroidpower.com/node/115

That's as far as I've got at the moment I'm afraid. Sorry I can't give you a better explanation.


Oh, please Don't apologise! That's a briliant answer. I shall have to read it a few more times before I even begin to get it. But at least it gives me something to go on.

Don't worry about the graph! I'm hopeless with graphs. lol

OK, so I was pleased to see it didn't replace serum tests, but was a further tool to understanding what's going on in someone.

Your doctor isn't very bright, is he? It's not the TSH and FT4 that tell you if you're over-replaced, it's the FT3. And if that wasn't high, then you weren't. :( You just weren't converting very well, so needed your FT4 high to get enough T3.


GG - not very bright doesn't come close to describing any of the GPs at my surgery. The one who said that about being over medicated is a tyrant. She is right, even when she is wrong, won't discuss anything and you can't discuss side effects of medication because they don't exist, even when they go away when you stop taking it, it's always down to something else!

I saw the newest one recently, my last hope of there being one decent GP, to do with breast discomfort. I was told to take ibuprofen even though I have a very long history of breast cysts pre menopause, no investigations offered despite all previous cysts got me a referral to the hospital PDQ but that was 15 years ago. I left the surgery in tears and worried about cancer, no reassurance at all. I self referred to a specialist in the end and paid for an ultrasound.

Unfortunately I have no choice but to continue at this surgery, the next nearest surgery is 10 miles away and the doctors there have the same reputation. I have never felt so alone in my health care.


It's disgusting, isn't it. The only profession in the world where they can get aways with such incompetence - and even, literally, murder!


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