[Conception and testing of a regional practice guideline using bronchial asthma as an example]. 
Frequently, there is a gap between publication and implementation of guidelines into clinical practice.  To improve adherence with guidelines, experts recommend among other things local adaptation of guidelines.  The goal of the present study was to conceptualize and test such an adaptation in the region of Neckar-Alb in Germany by using asthma guidelines as an example.  We conceptualized a three-step approach for regional guideline adaptation: 1) Compilation of existing national and international asthma guidelines by regional experts to develop a draft for regional asthma guideline; 2) regional consensus conference to discuss the draft with local physicians; 3) modified Delphi procedure using regional physicians as "experts" to get consent for the regional asthma guideline.  We defined consensus as reaching at least a 2/3 consent for each of the statements.  As starting point for the process of guideline adaptation, the regional experts developed a first draft of the regional asthma guideline including 132 recommendations.  60 out of 500 regional general practitioners (GP), internists and asthma specialists participated in the consensus process.  After the preparations of the regional experts and the regional consensus conference, only four recommendations had to be changed considerably during the Delphi procedure to reach the consensus criterion.  If the recommendations remained unchanged, the whole guideline might be disapproved because they were considered to affect the role of GPs by shifting responsibilities from GPs to asthma specialists.  As the result of the adaptation, the first regionally adapted asthma guideline for the Neckar-Alb region fosters the principal responsibility of regional GPs in asthma care, thereby surmounting resistance for implementation that former specialist-centered guidelines provoked.  Hence, the new guideline meets the requirements for successfully implementing the recommendations into clinical practice.