Preoperative laboratory testing: Implications of "Choosing Wisely" guidelines.

Preoperative laboratory testing is often necessary and can be invaluable for diagnosis, assessment, and treatment. However, performing routine laboratory tests for patients who are considered otherwise healthy is not usually beneficial and is costly. It is estimated that $18 billion (U.S.) is spent annually on preoperative testing, although how much is wasteful remains unknown. Ideally, a targeted and comprehensive patient history and physical exam should largely determine whether preprocedure laboratory studies should be obtained. Healthcare providers, primarily anesthesiologists, should remain cost-conscious when ordering specific laboratory or imaging tests prior to surgery based on available literature. We review the overall evidence and key points from the Choosing Wisely guidelines, the identification of potential wasteful practices, possible harms of testing, and key clinical findings associated with preoperative laboratory testing.