Microsoft Develops AI Tool That Can Diagnose ‘Sequentially’ Like a Doctor

Microsoft developed MAI-DxO, a research system designed to mimic doctors’ stepwise investigation of complex cases. It asks follow-up questions, requests tests and revises possible diagnoses as evidence emerges. Researchers tested it on 304 New England Journal of Medicine cases. Paired with OpenAI’s o3, MAI-DxO achieved 80% accuracy, compared with 20% average for physicians, and Microsoft reported lower testing costs. These results come from benchmark simulations, not clinical practice. The system remains a research project and is not approved for clinical use.