For BAT testing I follow Dr. Center's protocol on the YTCA.org website. I believe the Health Foundation hasn't updated their information on their website as if you know the new protocol the next paragraph in on the Health Foundation website it states fasting and fasting is no longer required per Dr. Center's new protocol.
I, as a breeder will hang on to my puppies until 6 months of age so when I do have a pet quality yorkie it will leave my house with up to date shots, BAT testing and spayed/neutered before leaving my home
Donna