Background: Routine preoperative laboratory testing for ambulatory surgery is not recommended.
Methods: Patients who underwent elective hernia repair (N = 73,596) were identified from the National Surgical Quality Improvement Program (NSQIP) database (2005–2010). Patterns of preoperative testing were examined. Multivariate analyses were used to identify factors associated with testing and postoperative complications.
Results: A total of 46,977 (63.8%) patients underwent testing, with at least one abnormal test recorded in 61.6% of patients. In patients with no NSQIP comorbidities (N = 25,149) and no clear indication for testing, 54% received at least one test. In addition, 15.3% of tested patients underwent laboratory testing the day of the operation. In this group, surgery was done despite abnormal results in 61.6% of same day tests. In multivariate analyses, testing was associated with older age, ASA (American Society of Anesthesiologists) class >1, hypertension, ascites, bleeding disorders, systemic steroids, and laparoscopic procedures. Major complications (reintubation, pulmonary embolus, stroke, renal failure, coma, cardiac arrest, myocardial infarction, septic shock, bleeding, or death) occurred in 0.3% of patients. After adjusting for patient and procedure characteristics, neither testing nor abnormal results were associated with postoperative complications.
Conclusions: Preoperative testing is overused in patients undergoing low-risk, ambulatory surgery. Neither testing nor abnormal results were associated with postoperative outcomes. On the basis of high rates of testing in healthy patients, physician and/or facility preference and not only patient condition currently dictate use. Involvement from surgical societies is necessary to establish guidelines for preoperative testing.