This website is great...It provides a wealth of information on the different labs and links to them. Just page down twice to see the table. I went to vetgen and upenn website and also requested information on tests they have for Yorkies...I'll update you when I get a reply back.
http://www.ivis.org/advances/Concann...r_frm.asp?LA=1
I know there are many wonderful breeders on this site that say they do genetic testing. It would be nice to get some recommendations from the labs you have used.