Physician response to, as well as outcome, cost and health effectiveness of the alkaline phosphatase component of an automated chemical screening panel in the primary medical care setting were studied. Out of 118 unexpected deviations, only one new diagnosis resulted--type A viral hepatitis. Because only one new diagnosis was made during the study period, estimates are tentative; however, when compared to other tests, the alkaline phosphatase component has a low health effectiveness (0.0298 Discounted Well-Years) and a low cost-effectiveness ($85,400 per Discounted Well-Years) and does not appear to be an economic way to make new diagnoses of therapeutically responsive diseases in the primary care setting.