It is possible to create an AI system that takes in symptoms and produces possible diagnosis. It would also be possible for it to check its model and figure out what additional evidence is most likely to change or clarify the diagnosis, and order a test to gather that evidence.
You would still need someone to perform all of the tests, and input the symptoms in. This would require some level of training itself, though not as much as a doctor.
Still, it would not be a trivial program to create, and the creators would be at a high risk of liability if it prescribed the wrong treatment. You would also need to get the legal system to accept this program as an acceptable substitute for a doctor, get clinics to buy this substitute doctor, then have patients who are willing to go to it. That last one is particuarly a hard sell since you would lose the human aspect; you want a human to explain what is wrong, be able to offer comfort, understand any special needs you may have, break bad news properly, etc.
Dean Carpenter, Professional programmer working on NLP
Source: Quora Digest