Microsoft reports that its MAI-DxO diagnostic system correctly solved 83% of 304 complex medical cases, compared with 36% for generalist physicians allowed to consult reference materials. The results come from a text-based simulation and do not establish that the system delivers better care to patients.
In its October 22, 2026 announcement, Microsoft presents the research as progress toward “medical superintelligence.” The work, published in Science, supports a more specific finding: an AI system can outperform individual generalists at gathering information and diagnosing cases inside a controlled evaluation.
The study tests how a diagnostician chooses what to ask next. Whether that advantage survives contact with patients, clinical teams, and hospital workflows remains unresolved.
The 83% Result Depends on Who Took the Test
The headline comparison used 304 clinicopathological conference cases published in The New England Journal of Medicine. Microsoft reports 83% accuracy for MAI-DxO, versus 36% for generalists using textbooks and internet references, and 22% for physicians without those resources.
The reference-assisted result is the more informative comparison for readers assessing the headline. Access to additional information substantially changed physicians’ performance, though the AI still scored considerably higher.
A second evaluation used emergency-department-to-admission encounters drawn from MIMIC-IV-ED. Microsoft reports approximately 80% accuracy for MAI-DxO against 47% for physicians. This extends the evidence beyond unusually difficult published teaching cases, though it remains a retrospective simulation.
Neither comparison establishes superiority over specialist teams. As TechCrunch’s reporting notes, the complex NEJM cases would typically involve specialists or physician teams, whereas the study compared the AI with generalists working individually.
MAI-DxO outperformed the participating individual generalists under the study’s conditions. The result does not demonstrate that it outperforms the clinical organization that would ordinarily handle such cases.
SDBench Tests What the Diagnostician Chooses to Ask
SDBench, short for Sequential Diagnosis Benchmark, changes the task from answering a fully specified medical question to deciding how to investigate one.
