Microsoft AI diagnostic system outperforms generalist doctors in Science study

Microsoft AI published a study in Science on Oct. 22 showing that its AI diagnostic system, MAI-DxO, correctly diagnosed complex medical cases in simulations 83% of the time, compared with 36% for primary care doctors and general internists working individually with reference materials. Microsoft AI CEO Mustafa Suleyman called the result a step toward “medical superintelligence.”

The system, also known as DxO, coordinates multiple AI agents that act like a panel of doctors, questioning patients, ordering tests and debating diagnoses. The simulation used complex cases from the New England Journal of Medicine. The researchers noted that such cases are usually handled by specialists or physician teams, who were not part of the comparison.

Microsoft tested DxO with models from companies including OpenAI, Google, Anthropic, Meta and DeepSeek. Its best results came with OpenAI's GPT-5 and GPT-5.5. The study's data suggested that much of the improvement came from more powerful underlying models, with Microsoft's orchestration system adding gains on top.

The company also said it is working with the Mayo Clinic to train a foundation model for healthcare, with a release planned for 2027. Microsoft will also partner with Beth Israel Deaconess Medical Center in Boston to evaluate DxO's clinical reasoning across different hospital settings.