Log in
Thyroid UK
93,594 members107,627 posts

Iodine test: blood or urine?

Hello. I am just wondering if anybody can help me with this question: what is the best way to measure iodine levels from blood or from urine sample?

Thank you.

E xx

29 Replies

The usual test is 24-hour urinary iodine. See here:


(Inasmuch as any test is "usual". Iodine testing seems to be rarely performed and is mentioned more in research than in its clinical application.)



Thank you Rod. I am getting some cash together for Blue Horizon tests, I know that NHS rarely do iodine test, I do not even dream of asking my GP for iodine test referral.

I wanted to check my iodine levels as since last year I was on a very basic diet and did not even use iodized salt so I thought this might be contributing factor to my poor state too. I do not know which one to chose, Blue Horizon do iodine - in blood, Genova uses urine as a sample.

I was just thinking which test would be more reliable in detecting iodine deficiency blood or urine test. Thank you once again for reply. E xx


This sounds a bit far out, but Amazon sells Pink Himalayan salt. This salt is from unpolluted sources laid down aeons ago. It has all 86 minerals body needs - among them, iodine, in the natural form which can be assimilated and dealt with by the body as it can deal with iodine from a natural dietary source, but the iodine in iodised salt as sold in supermarkets is out of balance. Dr Vogel does not recommend "man-made" iodised salt as it usually consists of completely refined and denatured salt with the iodine, which has been removed by refining processes, put back again but out of balance, meantime most of the other 85 valuable trace minerals have been removed by the refining. Celtic sea salt is also reckoned to be OK.

There are dietary sources of iodine like onions, do Google for others.

Sending very best wishes for your health


Thank you so much for your suggestion nostoneunturned :) I will look at Amazon to see more info about the product, I need to check my levels first, however salt should not harm me in anyway? I am afraid that I cannot eat onions:( I have to keep very basic diet, otherwise I do suffer from stomach upset. Best wishes for you too. E xx


Salt should not harm you. just use it as part of your diet as normal.


Hi Edysia, glad to see you here again.

As with any blood serum test, they only expose what is in your blood at the moment. That does not show the whole story. We are more interested in what is inside the cells and that is much harder to find out.

I've read about the iodine test and they give you a huge shot of iodine and if very little shows up in your urine, it possibly means your cells absorbed most of it. If you expel a large amount, it probably means you have sufficient. Of course, the science behind this has to be good enough to rely on.

Are you going to do the saliva test?


Hi Heloise. I am glad too see you too:) Shame that in this sad circumstances.

Thank you for replying. I do not think that I can get in UK test when they would give me iodine to digest first?? Are you talking about iodine saliva test? or cortisol saliva test? I am so sorry I am confused. E xx


I think that Heloise was referring to the iodine uptake test.



Sorry to be confusing. When you said you were doing some tests, I was curious if you were going to ALSO do the saliva test for cortisol. I don't know if conventional labs even process this test but I know Genova does it. I've always wondered whether adrenals caused thyroid problems or the other way around.

I think the iodine uptake is the one recommended for that test.


Its ok Heloise. No blood tests first, and later saliva, I have to spread out the costs. I know so far from one test that I have done in one hospital that my cortisol curve is reversed, as I expected as my sleep pattern is reversed, I do not sleep night only during a day from 4-5am onwards ( but I do not know if that was blood or saliva test, they did both but lost one of the results, so I do not know where my results coming from - from blood or saliva...- confusing now) .

My cortisol day curve is as follow:

9 am - 276 nmol/L

12pm -687nmol/L

3pm- 179nmol/l

6pm- 487nmol/L

8pm- 315nmol/L

so all over the place and as i said they took blood and saliva at the same time and they lost some results and they could not tell me if the above reading comes from saliva or blood. that was NHS test. E xx


Oh my, Edysia, even though I don't know much about either test, I know you should start high and slowly lower through the day. So did they ever treat your adrenals?

I've also been a night owl for most of my life. That's why I wondered if the adrenals go first. I was never treated with thyroid until I was in my fifties so I feel my adrenals were not functioning for a long time before that.

I had told Tony when he posted that you should try T3 and see if it doesn't help heal your adrenals.


I am not sure if I can tolerate T3, I cannot even go higher with my NDT, no more than 1 and 1/4 of a grain, I went up to 2 grains slowly but needed to go back down as my stomach and chest were hurting too much. My T4 is falling and T3 is raising slowly but it does not make me feel any better....

No they never treated my adrenals :( It is all sick, I know. I tried high and lower doses later in the day but I think I am utilizing NDT better in the evening, around 6 or 8 pm. Earlier I do not feel anything.


Edysia, I decided to try T3 for the reason you can't raise your T4. My main symptom is muscle problems and pain, lower back down legs. My free T4 and T3 were barely in range and every time I tried to raise my dose of Armour I would feel hyper, tight chest. I decided to stop all T4 and go straight to T3 only. I don't want to get complicated here but I am taking more T3 than my Armour gave me in my one grain. Actually I am taking twice as much T3 now. I have never felt hyper until now and I am going to lower my dose of T3 from 50 mcg. to 37 1/2.

That's the reason I suggested this to Tony because when I started on T3 and began raising it over a couple of weeks, I had no hyper symptoms at all. I could never do that with Armour.

I have two other problems, very high ferritin and very low vitamin D so I am still dealing with those but I am thinking that you should not be afraid of trying straight T3. It is not the same as T4.

I haven't done a saliva test but I have taken some licorice root, Siberian Ginseng, and adaptogens but read that T3 can help HEAL adrenals and that is why I have tried T3. stopthethyroidmadness.com/a...


My T3 level is quite decent , - it is 5.3 ( range 3.5-6.5) so quite good. the problem is I do not feel any benefits from T3 raise in my blood.

My main problem is iron level - in terms of vitamin and minerals ( my D3 and B12 are very good)

I cannot take iron due to inflammation in my abdomen, that is related to my ovarian fibroma.

I am NOT having gastrointestinal upset from iron but it seems to exacerbate my inflammation on cellular level.

That's why I am stuck. I need decent Iron level for T3 to work, and I cannot raise it because of the inflammation and this stupid tumor that nobody wants to deal with as they are scared to touch it.

I have tried licorice root and Ginseng but it gives me stomach upset. I know that T3 can heal adrenals but Iron is needed for T3 to do so, and I am stuck with my iron. :( Unless T3 only can work without the iron?

If not these issues I would try T3 only therapy with no hesitation. E xx



This makes it appear you have to stop all T4 to avoid reverse T3.


Have you tried Spatone iron water? Readily available and easy to take. If you take it with T4 though- it may make you feel worse as it did me [tongue tender etc] as it increases absorption of something not tolerated too well.

This showed to me that iron is important for thyroid. Selenium too but on T3, it may not matter.

If you have gut troubles to contend with, Kefir can help and also a daily fibre like Laxido will keep things moving. I take them both occasionally. Be wary of anything with Aspartame in it though.This is in prescription medicines.


Hi again Heloise. I have just look at stopthethyroidmadness and I think this is my case:

'Low cortisol: one might see this at one time of the day, but it’s more common to see two or more times in a day and especially in the morning. This is a very problematic state to be in and prevents you from getting out of your hypothyroid state. This is where the term “adrenal fatigue” comes into play. This will first result in hyper-like symptoms as you raise NDT, and next in excess RT3, putting your further into a hypothyroid state'



You know, E, in the old days we thought you only had the choice of T4 or NDT, now, we know there is so much more complicating the issue. I think I know how I raised my ferritin levels so maybe you should try it. I got powdered vitamin C and put a half teaspoon in a drink each morning. It was probably 2 or 3 grams but I never measured. Well, I just read that vitamin c will bind to iron. Maybe this will help you.


I already take vit C, 2-3 grams per day. I agree there is so many things out there, and it really gets so complicated :(



I just lost my message but I don't think that T3 ever becomes reverse T3 but T4 becomes either T3 or reverse T3. I do not think that T3 ever becomes reverse T3. I'm going to look through the above link myself and see what it says.


Thats' a good link Heloise, I think I have looked at it a few months ago but I did not think at that time about going T3 only.

According to this website, and that's what I thought the Reverse T3 can only be made from T4, so clearing this takes coming off T4/NDT and taking T3 for at least 8-12 weeks.

I am getting my pennies together to do Blue Horizon test and I am planning to do Reverse T3 together with T3 and some other stuff, I am going to calculate Free T3 to Reverse T3 ratio and if it is greater than 20 than I would have to consider T3 only therapy. I am just very scared how I am going to react to T3 only?? I really am, I do not need more problems? I live next to one of the worst hospitals in UK and in case of emergencies.... I am in trouble. Many times I preferred to scream and bite the pillow than go to our A&E.

I feel like I am going to die most of the time and if it wasn't for this tumor then it would be easier to experiment. I am still puzzled how am I going to increase my iron levels, having problems with inflammation?

Why do we have to be ill :(??? Sending you lots of love and warm wishes and be well E xx


Thank you, E, and you know so many of us felt your pain since you first posted on the blog and were very worried about you as well. And I also recall you had to give up on your studies for a degree of some sort. It was so sad. I'm so glad you have mustered up all this hope and energy to get well. I think there is an answer out there. Keep working on your adrenals. I wish I could send you some T3 to try for a week and you could see it's affect. It's not the scary substance some have made it out to be.

After three months I'm wondering if I no longer need quite as much because my receptors are working again. I have a few tests to take checking for inflammation which I'm sure I still have. I'm hoping my chronic pain subsides and then I will be a happy camper.

Just want to add that I now recall that when it comes to adrenals you have to find out which part is malfunctioning. That's when you choose cortisone instead.


Yes it is all so sad, I gave up study, my career, I became house and most days bed-bound, it is a real terror. I will do Reverse T3 test and I will try T3 I promise. I can always stop if it will make me worse , but I am still very scared, as I said the last thing I need is to get worse.

What tests for inflammation are you having?What dose are you on now Heloise? Exxx In case if I go to bed, it is 3:15 am here, I am saying good night to you :)


Yes, get some sleep!


Hope you got some rest.

About the tests, the CRP is a real marker for inflammation. That is C-Reactive Protein which I think is a heart attack worry as well. Sedimentation Rate, means something generally wrong with the system. I should look these up again. My P.A. also is checking liver function and an iron profile since ferritin is so high.

I just wanted to start a little cortisone since I'm sure the high ferritin is due to inflammation but doctors have their own ideas which usually prevail. I almost decided not to bother with it as I can also order prednisone

myself but I guess I will go along so as not to ostracize

myself. I'll let you know if anything pertinent shows up!


CRP is basic test, it is good for acute inflammations, Sedimentation rate is usually done with FBC. I am sorry I thought you are having more in depth tests and i was thinking what was that. Good luck with re-gaining your health. I will be off the computer today as I feel much more ill. Have a nice weekend. E x


Small correction, E. The ratio should be 20 or OVER

I think. stopthethyroidmadness.com/r...

The other problem is "pooling" if you read at the bottom.


Hi Edysia

I read your post yesterday - and wondered whether to send you some info on iodine.

I've been researching it in relation to COPD, which has overwhelmed me this year.

I too have wondered about getting tests done, but have not research that further yet. The protocol I decided to follow is American, (from Yoohoo iodine support group ).

I'm not recommending an iodine protocol to you. I don't know enough to do that.

I just find the information about how it used to be used in the past, very interesting and thought provoking.

Here is one persons view on it - you will find more of course, if you choose to google for more.


Sending warm thoughts



Have you joined the Iodine Yahoo Group? They have loads of advice about what supplements to take if you decide to try taking iodine. According to them an iodine loading urine test is the best one. I did this one here: purehealthshop.co.uk/shop/a... The owner of the site can send you the 50g dose of iodine you take at the start of the test too. Then the urine collection can be tested to see how much your body has retained.

1 like

You may also like...