Value of routine preoperative tests: a multicentre study in four general hospitals.

We have assessed the value of routine preoperative tests in asymptomatic patients and their influence on anaesthetic and surgical decisions. We studied 3131 ASA I and II patients from four general hospitals undergoing elective surgical procedures. A retrospective review of the medical records revealed that 853 (27%) patients had some abnormal test result, of which 465 (15%) were previously unknown and not suspected at the preanaesthetic visit; these comprised 8.6% chest radiographs, 5.6% electrocardiograms and biochemical tests, and 2.9% haematological tests. Perioperative management was altered in only 0.56-0.26% of patients, depending on the particular test. The present study confirms the need for selective and rational ordering of preoperative tests, the basis of which should be the clinical assessment during the preanaesthetic visit.