Critical appraisal in the practice of laboratory medicine

Critical appraisal is a key skill employed across the spectrum of laboratory medicine practice. It underpins the use of information that is relevant, of good quality and is meaningful. Relevance is answering the right question for the right patient at the right time, with quality ensuring provision of the right information. Meaningful is making the right decisions in order to deliver the right outcomes. Critical appraisal is about minimizing the risk of bias or 'departures from trueness' in all of the facets of laboratory medicine practice. It can be summarized in four steps: (i) a clear understanding and articulation of the problem being addressed - whether it be an analytical challenge, individual patient care or policymaking; (ii) verifying the methodological approach employed; (iii) assuring the reliability of the results and (iv) ensuring the applicability and implications of the results. Reference is made to a number of checklists that can be used to assist in the process of critical appraisal.