I had high thyroglobulin serum due to hyperthyroidism. Here is some info on this lab test...
"Thyroglobulin is present in the blood of all healthy individuals at very low concentration.
If thyroglobulin concentrations are initially elevated in a person diagnosed with thyroid cancer, then it is likely that thyroglobulin can be used as a tumor marker."
"People who have a goiter, thyroiditis, or hyperthyroidism may have elevated thyroglobulin levels, although the test is not routinely ordered with these conditions."
TPOAb is high with either Hashimoto's thyroiditis or Graves disease. In the early stages of Hashimoto's thyroiditis there may be no symptoms.
Selenium may lower TPOAb as shown in numerous studies. Results will vary depending on the person. I saw a 15% decrease in 6 months eating a few Brazil nuts daily.
Thyroglobulin is a protein made by thyroid cells - healthy and cancerous thyroid cells. In thyroid cancer patients, testing thyroglobulin levels is often used to test whether any thyroid cells are left in the body after a total thyroidectomy. If the thyroglobulin level stays the same or increases, it can indicate thyroid tissue (cancer cells) are left in the body. This only works in people who have had their thyroid removed because normal thyroid tissue also makes thyroglobulin. It cannot be used to identify cancer in people with a thyroid.
In someone with a thyroid, normal thyroid cells are producing thyroglobulin and it doesn't mean you have cancer. A high level of thyroglobulin can indicate hyperthyroidism, Graves disease, Hashimoto's, or a goiter (enlarged thyroid). Unless your thyroid is gone, I wouldn't assume a high thyroglobulin tumor marker result has anything to do with cancer, but I can understand the name of the test is very misleading. This test is not how thyroid cancer is diagnosed, although it can be used during the treatment of thyroid cancer (for people who have had a thyroidectomy) and can indicate a recurrence (again, in someone who has no thyroid).
I do know that if you have Hashimoto's and elevated levels of thyroglobulin antibodies, the normal test for thyroglobulin does not work and a different test is needed (and can result in abnormally low or high levels of thyroglobulin). Did your doctor also test you for thyroglobulin antibodies? Hashimoto's and Graves diseases are two autoimmune diseases which often involve elevated thyroid peroxidase (TPO) antibodies. Hashimoto's usually has an increase in thyroglobulin (Tg) antibodies, which can interfere with a thyroglobulin test, and Graves disease usually involves TPO antbodies and thyroid stimulating immunoglobulin (TSI). Since you have elevated TPO antibodies, it is possible you might have Graves or Hashimoto's and not know it. If your thyroid hormone levels are normal and you don't have any hypothyroidism or hyperthyroidism symptoms, then there is probably not much your doctor would do if you do have Graves or Hashi's except keep monitoring thyroid function. If you have Hashi's, it could trigger a false high thyroglobulin reading.
Why do I know anything about the thyroglobulin test? I have Hashimoto's with elevated thyroglobulin antibodies and TPO antibodies, and also had thyroid cancer. I had a thyroidectomy last year, and to monitor whether the cancer had spread or was growing, my endocrinologist did a thyroglobulin test, but had to order a "special" thyroglobulin test because the "standard" thyroglobulin test which uses antibodies to measure concentration of thyroglobulin does not work for people with elevated thyroglobulin antibodies like me because there are already auto-thyroglobulin antibodies present, and they have to measure using mass spectrometry instead.
I am not sure why thyroglobulin tumor marker test would be present on a panel of thyroid tests in the first place if it is not being used to measure thyroglobulin levels in thyroid cancer patients, but I am not a medical expert, and maybe it is part of a very thorough panel. Did they also do thyroglobulin antibody and TSI tests?
Please do not panic about thyroid cancer. Nothing from the thyroglobulin test indicates cancer (unless your thyroid has been removed, which since you didn't list any thyroid medication is probably not the case).