This large study using a reputable national database revealed that despite updated evidence-based guidelines that recommend against the practice, preoperative laboratory testing continues to be performed for most low-risk patients undergoing ambulatory gynecologic surgery. This study also further supports current guidelines in demonstrating no difference in surgical outcomes between low-risk patients who did and did not receive preoperative laboratory testing. Preoperative laboratory testing practices for low-risk patients undergoing ambulatory gynecologic surgery do not follow current evidence-based guidelines and should be re-evaluated.