83 Percent: The Accuracy Score That Put Microsoft's AI Ahead of Doctors in Complex Cases

The landscape of digital healthcare is shifting as major technology firms race to prove that artificial intelligence can handle the most difficult aspects of patient care. On Thursday, Microsoft released findings from a study published in the journal Science, revealing that its internal diagnostic system, MAI-DxO, correctly identified complex medical conditions in a simulation more than twice as often as generalist physicians.

The system, known as DxO, operates by coordinating a panel of AI agents that mimic a multidisciplinary medical team. These agents question virtual patients, order diagnostic tests, and debate potential diagnoses before arriving at a final conclusion. In the simulation, which utilized complex cases from the New England Journal of Medicine, DxO achieved an accuracy rate of 83 percent. In comparison, primary care doctors and general internists working individually with reference materials were correct only 36 percent of the time. It is important to note that such complex cases are typically managed by specialists or teams in real-world settings, who were not part of this specific comparison.

Microsoft is not alone in this pursuit; the company joins Google and OpenAI in claiming that its AI tools can match or exceed human performance. However, the data suggests that much of the performance boost comes from using more powerful underlying AI models, with Microsoft’s orchestration layer adding incremental gains. When tested with models from various providers, including OpenAI, Google, Anthropic, Meta, and DeepSeek, the highest results were achieved using OpenAI’s GPT-5 and GPT-5.5.

Cost and efficiency were also key metrics in the study. While GPT-5 alone scored 78.9 percent on complex cases at an estimated cost of $8,400 per case, adding the DxO orchestration reduced the cost by approximately $3,000 while raising accuracy by only about four points. The benefits of the orchestration system were less pronounced for emergency department cases, where accuracy and cost improvements were minimal between using the base model and the assisted system.

Despite the strong results, researchers noted that accuracy gains tend to diminish as models approach theoretical limits. Mustafa Suleyman, CEO of Microsoft AI, described the findings as a step toward "medical superintelligence." He stated that the company is collaborating with the Mayo Clinic to train a foundation model for healthcare, with a release expected next year. Suleyman believes this infrastructure will allow Microsoft to make significant leaps in the field, particularly in how medical records are processed and predicted.

The executive, who previously co-founded DeepMind, expressed confidence in the rapid pace of progress. He predicted that within the next 24 to 36 months, healthcare models will see an order of magnitude improvement in capability. Suleyman cited the "flywheel" effect seen in other AI sectors, where real-world usage helps identify gaps and improve the model. He expects this cycle to begin for medical records and clinical decision support by next year, potentially allowing clinicians to stream highly accurate predictions about how a patient's condition might evolve.

Moving beyond simulation, Microsoft is partnering with Beth Israel Deaconess Medical Center in Boston to evaluate DxO in real-world hospital settings. This study will compare the AI’s recommendations against those of human doctors in emergency and urgent care environments. Dominic King, vice president of Health at Microsoft AI, described the initiative as the largest study of its kind, aiming to provide compelling evidence for the system's scalability. As the company moves forward, it aims to integrate these tools into the broader clinical workflow, positioning itself as a leader in state-of-the-art medical decision support.

Microsoft has defined medical superintelligence as the capacity to surpass the strongest contemporary human-led health systems in medical reasoning and coordination. The company views this not just as a benchmarking exercise, but as a fundamental shift in how care is delivered. With existing products in dictation and radiology, Microsoft sees DxO as a natural expansion into clinical reasoning. Suleyman emphasized that the company is committed to accelerating the introduction of this technology, viewing it as a key differentiator in the competitive frontier AI market.