A Cochrane review included 3 studies with a total of 21 531 subjects. Routine preoperative medical testing (e.g. electrocardiography, complete blood counts and various serum measurements) did not reduce the risk of intraoperative (OR 1.02, 95% CI 0.85 to 1.22; 3 studies, n= 21531) or postoperative medical adverse events (OR 0.96, 95% CI 0.74 to 1.24; 2 studies, n= 20526) when compared to selective or no testing. Cost savings were evaluated in one study that estimated the costs to be 2.55 times higher in those with preoperative medical testing compared to those without preoperative medical testing. There was no difference in cancellation of surgery between those with preoperative medical testing and those with no or limited preoperative testing, reported by two studies.