Decision Thresholds

Abstract

Abstract This chapter draws on the classic papers by Pauker and Kassirer to describe a basic method of determining whether a test is likely to influence the management of a patient and is therefore worthwhile. It begins by defining the therapeutic threshold which is the probability of disease at which the clinician experiences equipoise between treating and not treating the patient when no more tests are available. It explains the major influencers of therapeutic threshold and how it might be calculated either empirically or using experience. The chapter then explains how therapeutic threshold relates to testing by informing the test threshold and test–treatment threshold, which describe the probability above and below which a test result will not change the decision to treat or not treat a patient.