The most highly trained service dogs are specially breed, socialized and trained from birth to 18 months when they begin their specialized service training. To properly train the dog to identify the scent and then work with a diabetic handler to properly alert, takes another 6 months to one year. That includes training the dog and the diabetic to become a successful alert team and also so that the dog can be properly accessed in public places.
When choosing a dog to train as a Diabetic Alert Dog you must know something about their breeding. Certain breeds such as German Shepherds make excellent Diabetic Alert Service Dogs because they use their noses and are very loyal and very protective.