Hi, I came across this thread and am in the same boat - your comment was very helpful.

I have a history of hyperthyroidism and high TPO and thyroid autoantibodies. I radiated in 2004-ish and the AB's slowly declined until being normal in 2015. the last test I had for them was 2017, they were normal as was my TSH and T4 on Synthroid. I've been well managed and balanced since then.

Then all of a sudden last week my TSH nearly doubled from 3.3 to 6.3 and my T4 declined only slightly from 1.14 to 1.07.

Anyway, I have a great endo and will see him in a couple of weeks. I will ask him about repeating the AB labs. I really had no idea that could crop up again 🙁 I am hoping it is just that my body wants my T4 a little higher and perhaps increasing from 88mcg to 100mcg will work. I was surprised to see OPs labs with TSH at 28 (!), perhaps that's a good sign that "only" 6.3 isn't as concerning.

FWIW, I'm glad yours turned out to be AB's (although I'm not sure what the treatment is...). I also have secondary adrenal insufficiency (my pituitary is shriveled and doesn't produce enough ACTH for my adrenals to make cortisol). so far (15 years) ACTH is the only pituitary hormone affected. I do not understand if somehow it now could make more TSH, that is usually from a tumor if it is pituitary related. none of this is great news, but it is helpful to have others in groups like these for ideas and support.