  Online symptom checkers have significant potential to improve patient care,
however their reliability and accuracy remain variable. We hypothesised that an
artificial intelligence (AI) powered triage and diagnostic system would compare
favourably with human doctors with respect to triage and diagnostic accuracy.
We performed a prospective validation study of the accuracy and safety of an AI
powered triage and diagnostic system. Identical cases were evaluated by both an
AI system and human doctors. Differential diagnoses and triage outcomes were
evaluated by an independent judge, who was blinded from knowing the source (AI
system or human doctor) of the outcomes. Independently of these cases,
vignettes from publicly available resources were also assessed to provide a
benchmark to previous studies and the diagnostic component of the MRCGP exam.
Overall we found that the Babylon AI powered Triage and Diagnostic System was
able to identify the condition modelled by a clinical vignette with accuracy
comparable to human doctors (in terms of precision and recall). In addition, we
found that the triage advice recommended by the AI System was, on average,
safer than that of human doctors, when compared to the ranges of acceptable
triage provided by independent expert judges, with only a minimal reduction in
appropriateness.
