If your TSH is in range, should your Thyroglobulin Antibodies be in range?

[TraceyLE]

I've just had to get private tests as my doctor will only test 6 monthly for TSH. They appear to come back normal except for the thyroglobulin anitbodies. If you are in range shouldn't the antibodies be in range too or am I missing something.......

I take 175 levo daily and the results seem good even though I'm feeling tired all the time.

Total T4 110 (59-154)

TSH 0.85 (0.27-4.2)

Free Thryoxine 18.6 (12 - 22)

Free T3 4.7 (3.1 - 6.8)

Thyroglobulin Antibody 427.6 (0 - 115)

I am hoping to get B12 tested to see if that is the problem.

Thank in advance

Tracey

[helvella Administrator Thyroid UK]

No. The following is how I see it.

The thyroglobulin antibodies are a measure of your immune system's attempt to clear thyroglobulin from your blood stream. That is likely to be related to the amount of thyroglobulin that is (or was) in the bloodstream. But not necessarily a simple "there's twice as much thyroglobulin so here will be twice as many antibodies" or "there's half as much thyroglobulin so there will be half the number of antibodies". Even if it generally goes in that direction there is likely to be some delay between changes in amount of thyroglobulin and changes in the number of antibodies!

Simply because you have lymphocytes attacking your thyroid does not itself mean that your thyroid cannot produce enough thyroid hormone. If the attack has destroyed a significant portion of your thyroid then it won't be able to make enough thyroid hormone - but until then there is a possibility that it will be able to keep the levels up.

And once you are taking a full replacement dose of thyroid hormone, your thyroid hormone levels should not vary too much because your thyroid will neither need, nor possibly be able, to make much. So your thyroid hormone levels will very largely depend on the tablets while the thyroglobulin antibodies depend on how much attack is going on.

The above is all very simplistic. It is quite possible that reducing the demand on the thyroid might also reduce the lymphocytic attack. But this whole area is complex and I certainly do not understand it all.

I do agree with getting B12 tested. Remember also, folates, iron/ferritin and vitamin D - if you can.

Rod

[TraceyLE in reply to helvella]

Thank you for that Rod, simplistic was what I needed and I sort of understand. At least I don't need to worry about that test result.

[Heloise in reply to TraceyLE]

I've been trying to figure out the meaning of antibodies coming from an autoimmune attack and so far this is what I have seen:

Although the presence of auto-antibodies is a part of the diagnosis of autoimmune disease, the relevance of auto-antibodies in otherwise health individuals is unknown.