Searching for evidence: a guide to finding the evidence in laboratory medicine

Laboratory medicine is strong in the basic scientific background that underpins the pathological rationale for considering the use of a test, as well as characterising analytical performance of laboratory procedures. Evidence of the impact of test utilisation on health outcomes and adding value to the patient's care pathway is more limited. However, purchasers and commissioners of laboratory services, as well as clinicians, are bombarded with a burgeoning literature on new biomarkers and devices, against a backdrop of fiscal constraints. This increasingly critical appraisal of both current practice, as well as new developments, demands that all health professionals are up-to-date in the knowledge of their subject, as well as being able to access and impart this knowledge in real time to their colleagues in the clinical team. This requirement for knowledge means that the laboratory medicine professional can be asked to provide information at any time, from a host of differing scenarios, and with a considerable variation in the depth of response being required. Thus, the biochemist may need to respond to a query from the Emergency Department on the one hand, to preparing the justification for a new test - or disinvestment in an old (and now inappropriate) test, to writing the case for a research grant proposal. All of these scenarios require clarity in the question being asked, and the ability to search for the evidence across a wide range of resources. This review takes the reader through the steps to efficient retrieval of good quality information.