Validation of surgical wound surveillance.

OBJECTIVE: To determine the sensitivity and specificity of standard infection control surveillance techniques for the identification of surgical wound infections.
DESIGN: Surveillance data collected by three infection control practitioners (ICPs) was compared to surveillance data collected simultaneously by a gold standard observer.
SETTING: University-affiliated, tertiary care hospital.
METHODS: Using standard infection control surveillance techniques (chart review and discussions with patients' nurses and physicians), ICPs collected surveillance data on patients on the General Surgery and Trauma Surgery Services on days 4 and 7 after surgery and then weekly for 30 days or until patients were discharged from the hospital. Simultaneously, a hospital epidemiologist collected surveillance data and examined each patient's wound daily.
RESULTS: Nine hundred twenty-five surgical patients including 537 trauma cases and 388 elective general surgery cases were followed postoperatively. The ICPs identified 67 surgical wound infections, and the hospital epidemiologist identified 80 surgical wound infections for a sensitivity of 83.8% with a 95% confidence interval (CI95) of 75.7% to 91.9%. Specificity was 99.8% with a CI95 of 99% to 100%. The sensitivity was the same for trauma surgery and general surgery, but incisional wound infections were more difficult to identify than deep wound infections. During a second validation period, sensitivity was 92.3% with a CI95 of 62% to 100%.
CONCLUSIONS: Standard infection control surveillance techniques have the same sensitivity for detection of surgical wound infections as they do for identification of other nosocomial infections. Accurate data on surgical wound infections can be collected without direct examination of surgical wounds.