Could you write a bit about the role of selenium in your treatment? Thanks.
I don't want to give any kind of medical advice especially without knowing the situation of others. If you are concerned though, it doesn't hurt to get blood work done. Following are the common things to test for if you think you may have Hashimoto's or thyroid issues.
Vit D, Ferritin, Thyroid peroxidase antibody (TPO), Thyroglobulin antibody (TGAb), Thyroid-stimulating hormone (TSH), Free T4 Test