Mapping the evidence base of pathology.

Evidence-based medicine (EBM) is a paradigm that is beginning to exert an influence in related fields such as surgery, general practice, psychiatry, and now pathology. For example, a survey has shown that 70 per cent of therapeutic interventions in clinical haematology delivered in a district general hospital were based on research-derived evidence. A prerequisite to evidence-based pathology is availability of, and access to, the evidence base. As a discipline, pathology has certain characteristics that makes information retrieval more challenging. Nevertheless, a number of evidence-seeking techniques can be utilized to maximize the chances of success: focusing the question, use of an evidence-seeking protocol, and application of methodological filters. A number of key information sources are reviewed for their usefulness and a comparison is made with the yield from the World Wide Web. Conclusions are drawn from an example of the evidence-seeking process based on a clinical scenario involving immune thrombocytopenic purpura.