Study objective: To evaluate the accuracy of a computer-aided consultation service using academic general internists and the Quick Medical Reference (QMR) diagnostic program: and to study the impact of the consultation on the diagnostic behavior of physicians caring for patients.

Design: Prospective study of the diagnostic accuracy of computer-aided consultation in 31 cases, as well as a prospective study of ward team diagnoses and opinions before and after consultation.

Setting: General medicine wards of two tertiary care centers.

Participants: Thirty-one patients identified as posing a diagnostic challenge and meeting eligibility criteria, as well as the housestaff caring for these patients.

Measurements and main results: After 6 months follow-up, diagnoses were established in 20 of 31 cases. The diagnostic sensitivity of the computer-assisted diagnoses, 85% (95% CI, 56% to 97%), was similar to that of the consult service physicians, 80% (95% CI, 55% to 94%), but better than that of the ward teams, 60% (95% CI, 33% to 81%; P = 0.03 using the binomial test). The consultation influenced the postconsultation differential diagnoses of the ward teams in 26 of the 31 cases (95% CI, 92% to 95%). House officers rated the consultation service as being educationally helpful in 25 of the 31 cases (95% CI, 62% to 94%).

Conclusions: Computer-aided diagnostic consultation, when provided by physicians familiar with the limitations of the system and capable of overriding inappropriate suggestions, was both accurate and educationally helpful in most cases. The system provided reasonable diagnostic suggestions not previously considered by the ward teams and these suggestions were valued sufficiently to cause alteration of the original differential diagnoses.