The most common cause for hypothyroidism is the autoimmune disease called Hashimoto's Thyroiditis, but some doctors don't really care about the cause -- including my former pcp. He never tested anything beyond TSH and FT4. If it had not been for my ENT, I would never have been tested for antibodies, nor had an ultra sound to find that I have nodules and a goiter.
To test for Hashimoto's you should have antibody testing (thyroid peroxidase antibodies, TPOab and Thyroglobulin antibodies, TGab). You should also have an ultra sound to check for goiter (enlargement) and nodules.
Do you think my to-be-doctor (internal medicine) would do an ultrasound my first appointment or would wait for hypo/hyper numbers?