National Institute for Health and Clinical Excellence guidelines on preoperative tests: the use of routine preoperative tests for elective surgery.

Clinical Guideline CG3 from the National Institute for Health and Clinical Excellence (NICE) makes recommendations on appropriate clinical practice in preoperative testing for elective surgery. Unfortunately, there is minimal evidence on which the guidelines could be based and therefore they were constructed on the basis of professional opinion. This resulted in the construction of a decision matrix of Byzantine complexity built on foundations of sand: surgical risk is estimated using an unvalidated ad hoc risk estimation method; anaesthetic risk is estimated using the American Society of Anesthesiologists (ASA) risk method that has been demonstrated to be incapable of generating consistent risk assessments. The resultant matrix may be suitable for use as a template for future research, but is extremely complex and inadequately rigorous for routine use.