Clinical guidelines: proliferation and medicolegal significance.

Guidelines seeking to influence and regulate clinical activity are currently gaining a new cultural ascendancy on both sides of the Atlantic. Statutory agencies may be charged with developing clinical guidelines, and civil courts, in deciding actions in negligence, could be influenced by standards of care expressed in guideline statements. Clinical guidelines are not accorded unchallengeable status: they have been subject to careful scrutiny by British and American courts to establish their authenticity and relevance. In the United States, compliance with clinical guidelines cannot be used as a defence against liability if a physician's conduct is held to have been negligent, and third party organisations can be held liable if their clinical guidelines are found to be a contributory cause of patient harm. Guidelines have not usurped the role of the expert witness in court. The importance the law attaches to customary practice means that atypical or bizarre guidelines are unlikely to be accepted as embodying a legally required standard of clinical care.