Evidence-based medicine in pathology: an introduction.

Evidence-based medicine (EBM) is a school of thought that has spread rapidly through medicine in the past 2 decades and is eliciting an increasing interest in Anatomic Pathology and Laboratory Medicine. It has been defined as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients." The environmental factors that created a need for EBM and basic concepts of this discipline are reviewed. Methods for the accrual and critical appraisal of the validity of available evidence and its impact, applicability and usefulness in pathology practice are discussed. Basic concepts of bayesian data analysis with an emphasis on concepts such as prior and posterior probability and the use of "holdout" or "test" data are introduced. The future of EBM in pathology is discussed and potential applications of these concepts to pathology practice and research are proposed.