Microsoft Develops AI Tool That Diagnoses Patients Step by Step Like a Doctor

The model uses an “orchestrator” that coordinates a simulated panel of clinical experts to determine which questions to ask patients, which examinations to conduct and which tests to order.

Microsoft researchers have developed an artificial intelligence (AI) tool that diagnoses patients step by step, following a process similar to doctors, and was more than twice as accurate as general physicians in solving complex medical cases, according to a study published Thursday in Science.

The model uses an “orchestrator” that coordinates a simulated panel of clinical experts to determine which questions to ask patients, which examinations to conduct and which tests to order. The system updates its diagnostic hypotheses as new information becomes available, allowing it to determine the next steps in the evaluation.

Unlike existing medical AI models that analyze a patient's symptoms, laboratory results and imaging studies together to generate a diagnosis, Microsoft's tool follows a sequential approach. It evaluates the patient's medical history and physical examination findings before deciding which tests are needed and whether further investigations are required.

According to the researchers, the tool was tested on more than 300 unusual and complex medical cases. It was more than twice as accurate as general physicians using textbooks and the internet to assess patients and determine diagnoses. The model also outperformed human physicians in scenarios drawn from a major database of emergency department admissions.

Microsoft AI Focuses on Diagnostic Accuracy and Efficiency

The researchers said conventional evaluations of medical AI systems often rely on multiple-choice questions, which may not reflect the complexity of real-world clinical practice.

“AI has become very good at getting a 100% pass rate on those,” said Dr. Dominic King, corporate vice president of the health unit at Microsoft AI. “But of course, that's not real-world. No patient ever came to see me with a nice summary.”

The study also found that diagnostic workups designed by the AI orchestrator cost less than those conducted by human doctors. Researchers said the assessment considered not only diagnostic accuracy but also how carefully and efficiently the system selected tests and investigations.

“We're not just measuring the accuracy of the systems. We're also measuring how judiciously and carefully it goes through a diagnostic work-up,” said Harsha Nori, head of AI at Microsoft AI Health.

Next Step: Testing in Emergency Departments

Microsoft researchers will next evaluate the tool's ability to triage patients in emergency department waiting rooms through a collaboration with Beth Israel Deaconess Medical Center in Boston.

The planned evaluation will examine the system's potential to support patient assessment in emergency care settings.

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