Preoperative investigation of the surgical patient

Preoperative investigations can be used to improve care and to reduce or inform patients of risks associated with surgery. However, they may be costly and can lead to harm. Selecting appropriate tests can be difficult, particularly in patients undergoing complex surgery or with multiple co-morbidities. Guidance, both local and national, is usually available. In addition, the experience of colleagues, including those from other specialties, can be invaluable. Understanding the statistical and clinical significance of investigation results is important for their appropriate interpretation.