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Confusion over different unit measurements in blood tests

Kenley profile image
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I am confused about the different units given in blood test results. For example my Thyroid Peroxidase Antibody TPO Ab result done privately in March with Medichecks) was given as:

295.7 IU/mL - Ref range 0.00 -34.00

The latest test result (done with the NHS) was expressed as:

62.1 ku/L - Ref range 0.00 -5.60

I believe that the first is International Units per millilitre and the second Kilo Units per litre but I can't undestand how to compare the results.

I have Hashimotos and have gone gluten free to see if it makes any difference to the antibodies but I am struggling to make sense of anything when they keep using different measurements - numbers not being my strong point anyway.

Also, when I have paid for tests privately, I also get a Thyroglobulin Antibody TG Ab test done (last one was 589.200 IU/mL ref range 0.00 -115.00) but the NHS will not do this. Does it matter? Should I only bother about the TPO?

Grateful for any help.

Thanks

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Kenley
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helvella profile image
helvellaAdministratorThyroid UK

Kenley,

For antibody tests, the results and ranges are widely varying.

Draw a line on a piece of paper. At the left end, write 0. About one tenth of the way along, write 34.00 on top of the line, and 5.60 underneath the line.

Plot 295.7 above the line based on where 34.00 is.

Plot 62.1 underneath the line based on where 5.60 is.

Truth is, both results are far above the reference limit. Exact position doesn't really matter.

Also, for some of these tests, once a definitive positive result has been reached, they do not continue the process to get to an accurate number. Once shown to be way over range, the view seems to be that whether you have 295.7 or 2957 isn't of any relevance.

SlowDragon profile image
SlowDragonAdministrator

The point is all the results confirm you have Hashimoto's also called autoimmune thyroid disease

Are you on Levothyroxine, Thyroid hormone replacement? If so how much

Have you got recent TSH, FT4 and FT3 test results

With Hashimoto's low vitamin D, folate, ferritin and B12 are extremely common. Always get actual results and ranges. Post results when you have them, members can advise

Hashimoto's affects the gut and leads to low vitamin levels

Low vitamin levels stop Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

But don't be surprised that GP or endo never mention gut, gluten or low vitamins. Hashimoto's is very poorly understood

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

thyroidpharmacist.com/artic...

thyroidpharmacist.com/artic...

amymyersmd.com/2017/02/3-im...

chriskresser.com/the-gluten...

scdlifestyle.com/2014/08/th...

drknews.com/changing-your-d...

Kenley profile image
Kenley in reply to SlowDragon

Thanks to you both for your replies. Yes I have been on Thyroxine for some years now - 125mg. I have secondary Hypothyrodism so my TSH is always very low which was why the NHS refused to treat me for years. Tried to fob me off with anti-depressants and HRT. I was not depressed, just miserable because I was ill, so I took myself off to see Dr Barry Peatfield about 10 years ago and he diagnosed me with Hashimotos and got me on Armour Thyroid. I got quite a lot better but the NHS only took me back on when I showed them blood tests I had had done privately which showed my T4 and T3 was practically non-existent.

Since then I have got quite a bit better but problems with weight still persist. I have done loads of research over the years and more recently looked into Izabella Wentz's website and listened to lots of her web lectures and interviews and it was this which prompted me to see if going gluten free made any difference. I am not aware of any obvious gut problems but I now realise that they can be there and causing problems even if we do not think we are suffering with a leaky gut. I have only been gluten free for just over 5 weeks and don't notice any difference yet. That is why I wanted to monitor the Thyroid antibodies. I thought if the antibodies were going down then the gluten free approach was working. If not, I would reintroduce gluten. I'm not fussed when eating at home but avoiding gluten when eating out is a real problem as it sneaks in everywhere, and something that would be gluten free if you prepare it at home, is often not in a restaurant.

Have just had very thorough bloods, including Vit D, iron, bone profile, glucose, cholesterol, etc and all is in order except for the thyroid. ESR a bit high, but that just seems to show that there is some inflammation in the body and I presume that is because of the thyroid antibodies.

Interestingly, my GP (not the one who fobbed me off years ago), another doctor and a pharmacist, have all agreed that going gluten free could help, so slowly the tide is beginning to turn.

This is a wonderfully helpful forum which I only discovered recently. I was a member years ago of Thyroid Disease Org but that seems to have disappeared.

SlowDragon profile image
SlowDragonAdministrator in reply to Kenley

Antibodies take months/years to lower, not something that happens overnight

Mine have halved in 18months GF

Like many on here I routinely test all thyroid levels privately. NHS does not routinely test FT3 or antibodies

Eating in restaurants is getting better and they should be helpful

Eating at friends and family is definitely tricky

But it does need to be 100% to be effective

Avoiding cross contamination too - eg shared butter dish, toaster etc

SeasideSusie profile image
SeasideSusieRemembering

Kenley

It doesn't really matter what the units of measurement are. What matters is where you are in relation to the range. In both of your tests you are way over range and that tells you all you need to know i.e. that you are positive for autoimmune thyroid disease.

Once you have confirmation then further testing is irrelevant unless you want to see if the measures you are taking to try and reduce the antibodies are effective. But antibodies fluctuate anyway, so it's not really that important to retest.

It doesn't matter in your case that the NHS don't do TG antibodies. Your TPO are positive so that's confirmation of Hashi's. If TPO were negative, it's worth doing TG because you can be negative for TPO and positive for TG which would also confirm Hashi's. Unfortunately, the NHS seems to have had a bypass where that information is concerned.

Kenley profile image
Kenley

Thanks SeasideSusie for explaining about the TPO/TG. I did wonder whether it was worth testing to see if I could get the antibodies down but maybe they will continue to fluctuate anyway, as you say.

humanbean profile image
humanbean

You can avoid worrying about units of measurement and reference ranges by using percentages.

To give you an example...

A few years ago I had three ferritin tests in about a year.

Result 1 was 21

Result 2 was 67.7

Result 3 was 51

It looks as though my ferritin got a lot better then got worse again.

But the reference ranges were different for each result. So instead of looking at the actual numbers if you look at how far each result was through the reference range as a percentage, then you get a different picture :

Result 1 was 6%

Result 2 was 14%

Result 3 was 28%

So it is clear that there was actually a continued improvement in my ferritin throughout the year. The original numbers were misleading and couldn't be directly compared because of the difference in reference ranges. But the percentages can be compared and give the true story.

People can overcome differences in units of measurement in exactly the same way.

Kenley profile image
Kenley

Thanks. That's very helpful

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