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Thyroid UK
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Understanding blood test results

Hi - I'm fairly new on here and I'm just looking for a bit of help after a recent set of blood tests please.

I've had an under active thyroid for about 14 years and I'm currently taking 125mcg thyroxine daily - a highish dosage due to some other meds that I take.

On my most recent test, my relevant results were;

T4 - 12.9 (expected range 9.01-19.05)

TSH - 0.2 (expected range 0.35 - 4.94)

Liver function (ALP) - 36 (expected range 40-150)

My GP hasn't followed up on any of these - does anyone think I should? I tried reducing my thyroxine a couple of years ago, but started to get some of the initial symptoms back again, so was advised to keep it at 125.

I still have really sore feet first thing in the morning, cold hands and feet and occasional choking spasms, so not sure that it's totally under control.

I've seen lots of posts mentioning T3 and wondered if that could be of benefit to me? Any suggestions would be appreciated.

15 Replies

In order to know if you have a conversion problem you will need a blood test that looks at ft3 and ft4. Mid to high range ft4 with low ,or below range ft3 would suggest a conversion problem. You also need to look at factors which contribute to ft4 to ft3 conversion such as ferritin, folate, vit b12.& vit d. If any of these are low it can inhibit conversion so that should be addressed before adding t3.

Just to add 125mcg levothyroxine is not a high dose, many people average out at 125-150 mcg and some require doses of 200-300mcg.

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Thanks for the feedback - some useful things to follow up on there. I'm surprised when you say my dosage is average - I have over 30 clients who are prescribed thyroxin and only one is on a higher dosage than me.


Perhaps they are all under-medcated - but having in range results are told they are fine by their GP 😊


Before you consider T3 its vital that




Vit d3

Are all tested as unless they are at least halfway in their ranges your body simply cannot convert the t4 in levo into the T3 that every single body cell needs to function

Its also vital that free t3 is tested

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Thanks for that - do you find that GP's generally aren't keen to test for T3?


GP's can request FT3 test - labs often refuse if TSH in range - madness !

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Its NHS labs that ignore free t3 requests

Your GP needs to put ? Central hypothyroid on the form then usually they do it


I still have really sore feet first thing in the morning

You could look up plantar fasciitis. It's a common symptom amongst people who are hypothyroid and usually indicates low T3, I think.


I've suffered with sore feet pretty much my entire life, but it got really, really bad in the 5 - 10 years before I started treating my thyroid. It would be agony to put my feet to the floor when I first got up in the morning. And walking down the stairs for breakfast was excruciating because my ankles wouldn't bend. Most of the pain would fade away within the first hour or 90 minutes of getting up - only to return the next day.

Improving my T3 seemed to do the trick and the problem has gone away with no other treatment necessary.


Thank you - another avenue to explore!


Sharon my husbands feet were agony till he switched to NDT


I'm sure you've already looked this up for yourself :

Having lower than normal ALP levels in your blood is rare, but can indicate malnutrition, which could be caused by celiac disease or a deficiency in certain vitamins and minerals.

Source : healthline.com/health/alp

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I did see that - don't think I suffer malnutrition, but deficiency in some minerals could be a possibility...


You also need to know if you have Hashimoto's- (high thyroid antibodies) Doctors tend to call it autoimmune thyroid disease, rather than Hashimoto's

Do you know if Thyroid antibodies have ever been tested? If not ask for these to be tested, plus checking vitamin D, folate, ferritin and B12 is extremely important before considering adding T3

Ask your GP to test, plus FT4 & FT3 - very unlikely they will be keen to do so, or even if they request all the tests from the lab, the lab often don't do them. But give it a try.

Always get copies of the results including ranges

Alternatively many of us on here get private tests


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. £99 for DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after test

If vitamins are too low then cells struggle to use thyroid hormones. If high antibodies and Hashimoto's then very common to have poor gut function, with resulting low vitamin levels due to malabsorption. "Leaky gut" often includes food intolerances, most common is gluten. We don't have to have any obvious gut issues.

Changing to a gluten free diet can help improve symptoms and may slowly lower antibodies too

Plantar fasciitis (sore feet) is suggestive of poor conversion of T4 to T3

Once you have improved vitamins (if required) and gluten free if need be, then adding very small amount of T3 and reducing T4 may be needed.

Read as much as possible about Hashimoto's.

Thyroid Uk is he home of this support group

The Thyroid Pharmacist website has masses of info about Hashimoto's. Also Amy Myers, Chris Kresser, scdlifestyle.com, & DrKnews.com

Majority with Hashimoto's are gluten intolerant, (no test available) but about 10-15% are coeliac. Coeliac blood test is notoriously unreliable. Endoscopy only reliable test.

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Thank you for the huge amount of info - just the kind of thing that will give me some direction on the research I need to do!


Hashimoto's can mean, despite good diet, that we don't absorb the nutrients, hence the malnutrition.

Gluten intolerance or silent coeliac do not have to have any gut symptoms at all.


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