Evidence Based Medicine; Pre and Post test Probabilities and Fagan's Nomogram

Emergency physicians face numerous questions regarding proper management of patients and selection of the best laboratory test or imaging every day. Knowledge on screening performance characteristics of the diagnostic tools used in this department plays an important role in finding the answers to these questions. We assessed these characteristics in the previous parts of educational article series in Emergency journal. In the present manuscript, we will describe how to use these screening characteristics for selecting the right diagnostic tools.