A complete set of thyroid tests should include thyroid stimulating hormone (TSH), serum free thyroxine, serum free triiodothyronine (FT4 and FT3), and an anti-T3 test, which is an anti-triiodothyronine test. In addition to this, there are antibody assays, including TSH receptor antibodies, TSH receptor stimulating antibodies, and peroxidase antibodies, which are diagnostic criteria to help diagnose thyroid disease. Thyroid tests should also include iodine-131 uptake rate and thyroid ultrasound, which can help identify other diseases. These are the full set of tests for thyroid function. If there are nodules in the thyroid, a fine needle aspiration test can be done again when doing this differential.