OFA Thyroid Number. The OFA Thyroid Number on your dog's certificate will be in this format: AS-TH12/28M-T. The table below shows how to interpret these results. AS = Breed Abbreviation (Australian Shepherd in this case) TH = Test type (TH=Thyroid) 12 = Certificate Number M = Dog's Gender T = The dog has a permanent ID, such as a tattoo or microchip The Thyroid Number itself does not indicate a test result. Owners must consult the OFA report directly for the Thyroid result. Thyroid test results may be listed as Normal or may indicate a variation in thyroid production, thyroglobulin autoantibodies, or thyroid stimulating hormone. The abbreviations for these three measures are: FT4, cTSH, and TgAA. Normal - Normal results indicate that FT4 and cTSH are within a normal range, and TgAA is negative. Positive Autoimmune Thyroiditis - FT4 is less than normal, cTSH is greater than normal, and TgAA is positive. Positive Compensative Autoimmune Thyroiditis - FT4 is within a normal range, the cTSH is greater than or equal to a normal range, and the TgAA is positive. Idiopathically Reduced Thyroid Function - FT4 is less than normal range, the cTSH is greater than normal range, and the TgAA is negative. Any dog with thyroid functionality other than normal should not be entered into a breeding program. Dogs with abnormal thyroid function can pass on genetic hypothyroidism (reduced thyroid function) to their offspring.