[Elaboration and critical evaluation of clinical guidelines].

Clinical guidelines are documents to help professionals and patients select the best diagnostic or therapeutic option. Elaborating guidelines requires an efficient literature search and a critical evaluation of the articles found to select the most appropriate ones. After that, the recommendations are formulated and then must be externally evaluated before they can be disseminated. Even when the guidelines are very thorough and rigorous, it is important to know whether they fulfill all the methodological requisites before applying them. With this aim, various scales have been developed to critically appraise guidelines. Of these, the AGREE II instrument is currently the most widely used. This article explains the main steps in elaborating clinical guidelines and the main aspects that should be analyzed to know whether the guidelines are well written.