This is important information to have, especially if you plan to take the dog hunting. OFA will also certify elbows, to show no joint deformity. CERF certifies that the eyes of the dog are clear. Von Willebrand's Disease Negative means that the dog has been screened for this disease. This disease is similar to hemophilia.
Many temperament tests exist to determine the aptitude of puppies from obedience to hunting.
If the breeder has conducted any temperament test, ask them to share the results with you. Responsible breeders take every precaution to produce puppies that are free of genetic diseases. If something unforeseen DOES surface, a responsible breeder will normally have a system in place to deal with your special circumstances. All of these details need to be discussed prior to buying the puppy. Responsible breeders accept a lifelong commitment to the dogs they breed.