Further on the health tests. It is better if you cross verify by going to the health registry sites themselves. You will need the full registered name of the Yorkie parents.
You can start here
www.chic.org this is a site that shows in one place some of the prebreeding/screening health tests done on Yorkies, CERF and OFA.
Or as this is a relatively new requirement and many breeders have yet to submit their paperwork to chic; go to
www.ofa.org for hips, elbows, knees (again the registered name of parents is required) and for eyes;
www.cerf.org. Oh yes and some breeders are preferring PennHip registry.
Liver Shunt testing has no main health database that I am aware of. Here you will need to see the Lab report on the test results for the breeding pair.
Hyperurocosuria - Bladder stones. Go to University of davis.
Cardio myleopathy - no health database
Kidney/Liver disease - no health database
On the AKC website
www.akc.org you can check out the breeding pair's record of wins
Also please check out the horizontal pedigree as well as the vertical pedigree. The vertical pedigree roughly speaking is that which is father/mother, grandfather/mother, greatgrand parents. The horizontal pedigree looks at siblings of the litter the parents come from. There are some studies which suggest that polygenetic conditions such as hip/elbow dysplasia is more accurately predicted by looking at within a certain litter, how many of that litter has/have the condition.
Good luck with your search.