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Thyroid UK
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I'm confused about TPO Antibodies

When I've read posts on here I've understood that TPO antibodies in the 100s meant Hashis. I think I may have misinterpreted this after reading: thyroiduk.org.uk/tuk/about_... where it says, "for the Antithyroid Peroxidase Antibodies, anything less than 150 mUI/ml or Ab Index no higher than 0.9. It is perfectly possible to establish a firm correlation between the levels of antibodies present and the severity of the illness."

My TPO level is 6 IU/mL (<34.0) - can someone interpret that figure for me please?

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AnneEvo

Ranges for all tests vary from lab to lab all over the country, they're not universal, so whenever you see a range it doesn't necessarily mean that it's appropriate for your own tests, you can only go by your own lab's range.

Your lab's limit for TPO Antibodies is 34. Anything <34 is classed as negative, anything >34 is classed as positive. Your result is 61 so positive for TPO Antibodies.

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Is her result 6 ie 6 IU/mL (<34.0)?

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Thanks shaws I can see that now I'm on my PC and I've rectified my mistake :)

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Mine is 6 Seaside Susie (6 IU/mL) But I was confused because the article I read says, "anything less than 150 mUI/ml or Ab Index no higher than 0.9. It is perfectly possible to establish a firm correlation between the levels of antibodies present and the severity of the illness." Am I misreading it, I take that as being Hashis if the reading is less than 150 mUI/ml and mine is 6? Sorry if I'm being dense.

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Sorry Anne, my mistake, I did misread that - should've gone to SpecSavers. Was on tablet, now on PC!!

OK, so I have found the quote you are referring to on Thyroid UK and it says

In general however, for Thyroglobulin Antibodies, the reference range should be anything less than 200 mUI/ml or Ab Index no higher than 0.9, and for the Antithyroid Peroxidase Antibodies, anything less than 150 mUI/ml or Ab Index no higher than 0.9

So they are talking about two different things there

(1) The measurement of TPO Abs in mUI/ml and

(2) The AB Index being no higher than 0.9

Your test result is showing TPO antibodies measured in mUI/ml or IU/ml which I believe is the same. Your result is nothing to do with the AB Index.

Back in 2000/2001 when I was consulting with Dr Peatfield, I had my thyroid tests done through a private lab which no longer exists. Their thyroid antibody tests were measured using the AB Index, and the TPO measurement was 'not greater than 0.9'.

I have never seen any antibody results on the forum using the Index, it's always been the mUI/L or IU/ml and the range for TPO is usually <34 with the labs used.

So, with a level of 6, you are nice and low so negative for Hashi's. My apologies for getting mixed up.

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It's ok. I realise though now what I've done. I've put the 2 together thinking it was saying if less than 150, there is a firm correlation........

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AnnEvo,

You need to read your results with the ranges your lab uses. So your result is 6 and it is <34 which is the range your lab uses so your result is negative for autoimmune thyroiditis (Hashimoto's).

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