Tzaylie was trained by Service Dogs By Warren Retrievers (SDWR), a non-profit organization in Madison, Virginia. They train and place dogs with individuals who are living with type 1 and type 2 diabetes, autism, PTSD, and seizure disorders. The organization was founded by Dan Warren, a diabetic, to "help people with invisible diseases and disabilities better manage their health."
Dan says that it is "all about the nose." Their dogs are trained to recognize changes in blood sugar. A diabetic who is very high, smells sweet. The dogs are trained to recognize the scent and once they learn to recognize the different smells, they are taught to alert on that scent as it is fluctuating. The dog will not stop alerting until something is done to fix the problem.
They only use labradors because they are highly trainable and eager-to-please. They have their own breeder host program where a specially bred litter of puppies can be raised with their mother for seven weeks in a warm and loving home environment until they are ready to begin their training.
Source: Noa Nichol, Modern Dog Magazine