Interpreting thyroid test results: Hi all I've... - Thyroid UK

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Interpreting thyroid test results


Hi all

I've been having no luck with my GP, so got Blue Horizon 11 test. I am on no thyroid meds. Any advice on what to do next much appreciated!

Symptoms: suspected i had hypothyroid for years - really feel the cold even in summer, exhausted ALL THE TIME, very poor sleep quality when i manage to sleep, unexplained low ferritin for years, dry scaly skin, mild depression, no get up and go, gained weight over last 5 years or so, unexplained muscle aches, the memory capacity of a goldfish, constipation despite good diet, etc.

Even i can see TSH is too high! and i know B12 is - but i take a supplement ,which explains why it is. So not bothered.

hs-CRP 0.93 <5.0 mg/L Ferritin 81.1 13 - 150 ug/L

Thyroid Function

TSH 3.77 0.27 - 4.20 mIU/L

T4 Total 105.0 66 - 181 nmol/L

Free T4 17.60 12.0 - 22.0 pmol/L

Free T3 5.31 3.1 - 6.8 pmol/L


Anti-Thyroidperoxidase abs 11.0 <34 kIU/L

Anti-Thyroglobulin Abs 18 <115 kU/L


Vitamin D (25 OH) 111 Deficient <30 nmol/L Insufficient 30 - 50 Consider reducing dose >175 Vitamin B12 H 641 Deficient <145 pmol/L New range Insufficient 145 - 300 Consider reducing dose >569

Serum Folate 20.70 8.83 - 60.8 nmol/L

53 Replies

Hi Rachel

Yes, your TSH is close to the top of the range but your FT4 and FT3 are about right for a "normal, healthy person".

What time did you do your test?

Did you fast overnight and drink water only - breakfast and any other drinks after the blood draw? I'm trying to find a reason for your high-ish TSH.

As you take B12, do you also take a B Complex to balance all the B vitamins? If you do take a B Complex, it will contain Biotin (B7) and this needs to be left off for a week before testing because if biotin is used in the testing procedure it will give false results.

Thanks. Yes, nothing to eat overnight and did before breakfast. I take B complex, yes. I also take D3 supplement and have been treated recently for historic unexplained low ferritin, which explains normal ferritin reading. I was advised to get tested as I have every hypothyroid symptom under the sun!

Symptoms: suspected i had hypothyroid for years - really feel the cold even in summer, exhausted ALL THE TIME, very poor sleep quality when i manage to sleep, unexplained low ferritin for years, dry scaly skin, mild depression, no get up and go, gained weight over last 5 years or so, unexplained muscle aches, the memory capacity of a goldfish, constipation despite good diet, etc.

SeasideSusieAdministrator in reply to Rachel1958

Did you leave off your B Complex for 7 days before the test? If you didn't, you can't rely on those results being accurate. You could contact Blue Horizon and ask if biotin is used in the assay, but if they use the same lab as Medichecks then it's definitely used in the testing procedure, Medichecks has confirmed this and advise the 7 day break.

SlowDragonAdministrator in reply to SeasideSusie

We need to push both Medichecks and Blue Horizon added a prominent note about Biotin and any B vitamin supplements on their websites and on the paperwork posted out in test kits

SeasideSusieAdministrator in reply to SlowDragon

Someone did say that Medichecks now include a note in the instructions about leaving B12 off for 7 days. That came about after a member checked about biotin. It did make me wonder if they'd put B12 by mistake and they actually meant biotin. I haven't sent for a Medichecks kit for while so I haven't seen this.

SlowDragonAdministrator in reply to SeasideSusie

I noticed Blue Horizon addd a note about stopping Biotin a week before for some of their DNA testing

I had a medichecks test 2 weeks ago and it came with the Biotin warning. I had 2 tests 18 months ago when my TSH came in between 3 to 4, when I was taking Biotin. The real result was closer to 8.

Oh, good grief! So i may well be a lot higher tsh wise?

It is a possibility. I was highly symptomatic when the TSH came back between 3 and 4, so was surprised. I didn't realise about Biotin for a couple of months, so left off Biotin for a week, retested and TSH came in around 7.7. I think Biotin can give false highs and false lows, but stand to be corrected.

Rest easy (speaking to myself!) - i just googled it and it only has an effect if you're taking super mega high doses. Like about 10 times or more what i am! 100mg, for example. I take (when i take it)100mcg.

SeasideSusieAdministrator in reply to Rachel1958

That doesn't explain why Medichecks makes a general recommendation for stopping Biotin or a week before a test, they don't mention anything about it's OK to take X dose but not Y dose. And I'm sure fibrolinda below wasn't taking a mega dose and it affected her results.

Let's just wait to see what Blue Horizon say, shall we? This isn't the reaction i was expecting at all, tbh!

Gosh no mega dose just 200ug at the time. I believe because biotin is used in the testing it effects the reliability of some tests, even a small amount can send things out of whack. Hmmm mind you I do not trust my memory at all... Will try find the article

Thanks, my love. I have googled it and all the info was on mega doses!

I take Thorne Basic B complex which has got a high level of Biotin (400mcgish I think).

Mine is 100mcg. And i haven't been taking it regularly anyway. Maybe once a week.

SeasideSusieAdministrator in reply to Catsnkayaks

Thanks for that. Was the warning on the instruction leaflet?

I think it might have been in the referral letter for a blood draw test, or possibly the e-mail. There was definitely some sort of warning, because I noted that being new.

No warning for me in any form from Blue Horizon. Which would seem to indicate that their tests must be ok, as this seems to be fairly well known in thyroid/blood test circles?

I have asked them anyway.

SlowDragon, I have both written to and spoken to Blue Horizon and have now heard back from one of their doctors.

He said that unless you're taking massive doses of biotin (over 5mg), it won't affect their tests. They checked with their lab.

He said that for some tests they recommend not taking a B complex the 12 hours before.

But the thyroid 11 isn't one of them.

So my test results are valid and not corrupted, which is good!

Ok, I'll ask them. So it will give a false high tsh result? Very surprising they don't tell you to lay off taking them as so many people take them these days. Plus i wasn't taking them every day.

Also, last time i was tested, 18 months ago, i was taking the same supplements but far more regularly and my results were:

TSH: 2.28 (0.3-4.2)

T4: 14.4 (9.0-23.0)

SlowDragonAdministrator in reply to Rachel1958

Have you ever had ultrasound scan of your thyroid?

You can have Hashimoto's and never have raised antibodies

No, I haven't. Oh dear - I don't like the sound of that!

Do my results indicate Hashimotos?

It has aiso been suggested i might have thyroid hormone resistance so things seem to be pointing to a genetic disorder, maybe?

SlowDragonAdministrator in reply to Rachel1958

Your current results show good FT4 and FT3. Slightly higher than average TSH, but you would struggle to get any medic to say these results indicate hypothyroidism

Median TSH graph

Suggest you look at possible food intolerances

Have you tried strictly gluten free diet?

Perhaps see a nutritionist

Also perhaps consider getting DNA testing

I AM a nutritionist. And i have IBS, food intolerances and allergies. Which are all under control.

That really doesn't explain all my hypothyroid symptoms though?

As i said, i know no GP will treat me. That is a huge part of my problem!

I'm following up suggestions about thyroid hormone resistance now. It has been suggested to me in 2 separate places (including on this thread) so seems worth a look at.

DNA testing looks interesting. I'll have a look.

Thanks for all this help - i really appreciate it xx

SlowDragonAdministrator in reply to Rachel1958

Blue Horizon do an even wider bundle of DNA testing

Did you use the Blue Horizon DNA test?

SeasideSusieAdministrator in reply to Rachel1958

I don't know how the results will be affected, I've just seen "will give incorrect lab test results", it's not just thyroid tests, other tests can be affected too.


Excess biotin in the blood from supplements can cause some, but not all, lab test results to be either falsely increased or falsely decreased, causing healthcare practitioners to misdiagnose and mistreat their patients.

Lots of articles found on Google

Oh, i see. Ok - so it doesn't necessarily explain the TSH results then. So, ignoring the B7 thing - what do you make of the results? i listed my symptoms above.

Thanks - i appreciate this!

Plus i'll write to Blue Horizon too. Feeling annoyed, as i may have wasted £100!

Just googled it and you have to be taking HUGE doses of biotin for it to affect test results.

SeasideSusieAdministrator in reply to Rachel1958

Until we know whether or not biotin was used in the assay, it's not really possible to comment on your blood test results because we don't know for certain which tests are affected, other than thyroid. The warning says that "some, but not all" tests can be affected.

If you find out that Blue Horizon do use biotin in the assay, and they don't warn about leaving it off, then I would ask them to send you a free kit so you can repeat the test without using biotin beforehand.

Ok thanks. I did some research - see above. I'm a nutritionist so quite interested in dosages of supplements!

For me stopping biotin for five days before test changed free t4 and free t3 with them dropping from top of range to scraping along the bottom of the ranges. TSH was slightly higher.

Which brand test did you use, Linda? I used Blue Horizon.

Just checked, blue horizon, although previous tests with medichecks before reading about biotin.

I've asked them about it. It's scandalous if they're sending us false test results without warning us about biotin. So, with Blue Horizon, your results changed when you stopped taking biotin? Just want to get all my ducks in a row for my correspondence with them!

I go with whoever tests are best value. Tests before learning about biotin were with both. High free t3/4 test before learning about biotin was actually with medichecks and first test after stopping biotin for five days was actually with blue horizon. But had been high in range and even over with both companies previously. This is the article I first learnt about biotin


Ok, so i have looked at Blue Horizon's terms and conditions and it says not to take biotin within 12 hours of taking the test. I hadn't taken it for days prior to the test, so i'm fine!

Also i looked at some individual tests which had instructions about biotin on and it says not to take within 7 hours if your daily dose is 5mg or more. Which is a HUGE dose.

I take a 100mcg dose when i take it.

Hope this clears things up a bit!

SeasideSusieAdministrator in reply to Rachel1958

I don't really need it clearing up. If Medichecks has confirmed to one of our members that no biotin should be taken for 7 days before testing because they use biotin in their assay then that's good enough for me, after all they are the ones doing the tests and I am happy to pass on their recommendation.

T3 is the active thyroid hormone which controls the metabolism and therefore the symptoms. Your Free T3 is near the top of the normal range, which is good and means that you are not hypothyroid.

Your combination of raised TSH and high in range Free T3 is unusual and is a strong indicator of a genetic condition: Impaired Sensitivity to Thyroid Hormone (more often known as Thyroid Hormone Resistance). It causes hypothyroid symptoms and requires very high T3 levels (often above the top of the normal range) in the body to overcome the resistance.

As it is genetic if there are other family members with thyroid problems, fibromyalgia, CFS, ME, Coeliac Disease, MS, Heart Disease or depression this would further support this possibility. Even if you cannot identify any family history of this it is still possible that you have this condition.

Rachel1958 in reply to HughH

Thanks so much, Hugh! So, as my GP has been quite resistant to the idea that i may be hypothyroid (for whatever reason!), do you think he will take notice if i turn up with those results?

We have a massive family history of depression. And my dad had heart disease. I also already have an autoimmune condition - rosacea.

HughH in reply to Rachel1958

Doctors seem to have a limited knowledge of thyroid issues and tend to rely almost exclusively of the TSH result and as yours is in the normal range will see it as being ok.

It is however worth mentioning the possibility of thyroid hormone resistance - you may have a more open minded GP and he may even be willing to refer you to an endocrinologist.

Rachel1958 in reply to HughH

I'll give it a go! Or can go private if i absolutely have to. I'm worth it!

Marz in reply to Rachel1958

HughH has written a book on the topic - available on Amazon ...

Rachel1958 in reply to Marz

Yes i bought it yesterday. Thanks Marz!

Rachel1958 in reply to HughH

Hugh, I've started self treating with T3 as per your book and am having amazing results. Thanks so much! I've just posted about it xx

HughH in reply to Rachel1958

It is a big step to self treat, but for many it is the only option. I am really glad that you are having such positive results.

Rachel1958 in reply to HughH

Thank you!

Yes, i had no option.

But i'm so glad i did. I'm soooo much better.

I've worked my way up through 25mcg, then 50mcg, as per the book.

Have just started 75mcg.

Does anyone else have any advice, given my results.

I have now established from Blue Horizin that my test results are not corrupted!

I realise that i have to self treat, as i can't see my GP doing anything...

Thanks, lovely people. x

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