SEQUENTIAL TEST SELECTION IN THE ANALYSIS OF ABDOMINAL-PAIN

Numerous decision-making tools exist to assist physicians in diagnosis management. However, the accuracy of available clinical information i s often ambiguous or unknown and current analytical models do not expl icitly incorporate judgmentally defined information. A model encompass ing both physician judgment and probability analysis was developed to accommodate such data. A problem requiring sequential diagnostic testi ng was structured utilizing the analytic hierarchy process (AHP). The case presented involved a patient complaining of upper abdominal pain who, after initial evaluation, did not need immediate surgery. Physici ans were faced with identifying the optimal sequence of diagnostic tes ting. The criteria used for test selection included minimizing risk, p atient discomfort, and cost of testing and maximizing diagnostic capab ility. Although at the onset the ''best'' test choice was unknown, the clinical picture indicated four test alternatives: upper gastrointest inal series (GI), abdominal ultrasonography (US), abdominal computed t omography (CT), and upper gastrointestinal endoscopy (END). Based upon the relative preferences of the criteria utilized, the AHP analysis i ndicated that upper GI series was the optimal first test. Given a nega tive test, posterior probabilities were calculated using Bayes' theore m, resulting in a new estimate of diagnostic capability. The AHP analy sis was reiterated, identifying abdominal ultrasonography as the optim al second test. This analysis may be repeated as many times as necessa ry. Sensitivity analysis demonstrated that changing criteria preferenc es may alter the choice of tests and/or their sequence.