A man walks into a doctor's office. The doctor says, "Mr. Smith, I'm sorry, but I have some bad news for you. We have your wife's test results, but, due to some mix-ups in the paperwork at the lab, I'm not sure if your wife is the patient with Alzheimer's or rabies."
"What do I do?", asks the man.
"Oh, that's easy", says the doctor. "Take for for a drive in the country and let her out of the car. If she comes home, shoot her."