Survey study of anesthesiologists' and surgeons' ordering of unnecessary preoperative laboratory tests

Nearly 20 years ago it was shown that patients are exposed to unnecessary preoperative testing that is both costly and has associated morbidity. To determine whether such unnecessary testing persists, we performed internal and external surveys to quantify the incidence of unnecessary preoperative testing and to identify strategies for reduction.

The medical records of 1000 consecutive patients scheduled for surgery at our institution were examined for testing outside of our approved guidelines. Subsequently, 4 scenarios were constructed to solicit physician views of appropriate testing: a 45-year-old woman for a laparoscopic ovarian cystectomy, a 23-year-old woman for right inguinal herniorrhaphy, a 50-year-old man for a hemithyroidectomy, and a 50-year-old man for a total hip replacement. One or more of these scenarios were sent to directors of preoperative clinics (all), United States anesthesiologists (all), gynecologists (cystectomy), general surgeons (herniorrhaphy), otolaryngologists (thyroidectomy), and orthopedists (hip replacement). Potential predictors of ordering and demographic information were collected.

More than half of our patients had at least 1 unnecessary test based on our testing guidelines (95% lower confidence limit = 52%). The 17 responding preoperative directors were unanimous for 36 of the 72 combinations of test or consult (henceforth "test") and scenario as being unnecessary. Among the 175 anesthesiologists responding to the survey, 46% ordered 1 or more of the tests unanimously considered unnecessary by the preoperative directors for the given scenario. Among 17 potential predictors of anesthesiologists' unnecessary ordering, only training completed before 1980 significantly increased the risk of ordering at least 1 unnecessary test (by 48%, 95% confidence limits >29%). Anesthesiologists were 53% less likely to order at least 1 unnecessary test relative to gynecologists for the cystectomy scenario, 64% less likely than general surgeons for the herniorrhaphy scenario, 66% less likely than otolaryngologists for the thyroidectomy scenario, and 67% less likely than orthopedists for the hip replacement scenario. The 95% lower confidence limits were all >40%.

The percentage of patients with at least 1 unnecessary test is a suitable end point for monitoring providers' ordering. The incidence can be high despite efforts at improvement, but may be reduced if anesthesiologists rather than surgeons order presurgical tests and consults. However, anesthesia groups should be cognizant of potential heterogeneity among them based on time since training.