Role of routine laboratory investigations in preoperative evaluation.

Traditionally, routine investigations prior to surgery are considered an important element of preanesthetic evaluation to determine the fitness for anesthesia and surgery. During past few decades this practice has been a subject of close scrutiny due to low yield and high aggregate cost. Performing routine screening tests in patients who are otherwise healthy is invariably of little value in detecting diseases and in changing the anesthetic management or outcome. Thorough history and investigation of positive answers by the clinicians, combined with physical examination of patient represents the best method for screening diseases followed by few selective tests as guided by patient's health condition, invasiveness of planned surgery and potential for blood loss. A large number of investigations which are costly to pursue often detect minor abnormalities of no clinical relevance, may be risky to patients, cause unnecessary delay or cancellation of surgery, and increase medico-legal liability. An approach of selective testing reduces cost without sacrificing safety or quality of surgical care.