This month’s issue of JAMA addresses the question “Does this patient have a blunt intra-abdominal injury?” as part of the always-popular Rational Clinical Examination series.
The systematic review of the literature summarizes the accuracy of findings for your blunt trauma patient in diagnosing intra-abdominal injuries. Specifically, likelihood ratios (LR) are summarized. These LRs can be used to plot on the Bayes nomogram below. You draw a straight line connecting your pretest probability and the LR. This yields your posttest probability.