Pets cannot talk and tell us what hurts or what is going on with them, so veterinarians have to be skilled in the art of diagnostics. A thorough physical examination goes a long way in determining what is happening with a pet that is not feeling well, but often leaves us with a list of different potential diagnoses. The veterinarian then has to choose which diagnostic tests need to be run to narrow it down to a definitive diagnosis and then choose a proper treatment plan.