[Practice guidelines: let us sort them].

A growing number of clinical practice guidelines (CPG) is published. This is understandable because CPG are the corner stone in the evaluation of professional practices (EPP). One cannot deny that EPP is necessary. However, in order for the EPP to reach their objectives, which are to use our resources better and to improve health-care, CPG at our disposal should be of good quality, both in their form and in their content. This is not always the case. What is more, health-care professionals are often not properly trained to distinguish "good" from "not so good" CPG. In this context, the Société française de biologie clinique has created a working group on "CPG and Evidence-Based Laboratory Medicine (EBLM)". One of the main objectives of our group is to publish critical appraisals of CPG on a regular basis in the Annales de Biologie Clinique (ABC). Thus, the ABC will follow the example set by other medical journals, for example in France: Prescrire. We will more particularly appraise CPGs in relation with laboratory medicine. In this first article, we describe the methods that we will use in order to distinguish "good" from "not so good" CPG. Just like Prescrire as well as like many others, our first tool will be the AGREE instrument, which is quite consensual at an international level. The AGREE tool makes it possible to appraise quite easily, and in a reproducible way, the methodological quality of CPG. We also briefly discuss the more complicated methods that can be used to make judgments about the content of CPG, bearing in mind that equity, patients' autonomy, balancing risks and benefits, are the four universal principles of medical ethics, that is of good medicine, that is of EB(L)M.