[Clinical practice guidelines (II): searching and critical evaluation].

Clinical practice guidelines have unique characteristics of the Internet era in which they are starting to be increasingly popular. The fact that they are often elaborated by governmental agencies and are not published in conventional journals means that they may not be accessible using the usual search methods employed for other types of scientific studies and documents (clinical trials, reviews, etc.). The Internet has become an essential tool for locating clinical practice guidelines, and meta-search engines, specific databases, directories, and elaborating institutions are of special importance. The relative lack of indexing of clinical practice guides means that Medline and Embase are not as useful in this context as in searching for original studies. With the aim of evaluating the validity, reproducibility, and reliability of clinical practice guidelines, a series of European institutions designed a tool to evaluate clinical practice guidelines at the end of the 1990s. This instrument, named AGREE, aims to offer a framework for the evaluation of the quality of clinical practice guidelines. It can also be useful in the design of new clinical practice guidelines as well as in the evaluation of the validity of guidelines to be updated or adapted. The AGREE instrument has become the reference for those that use guidelines, those that elaborate them, and for healthcare providers.