BackgroundPrioritization of anesthetizing locations for infection prevention depends on having a high positive predictive value for the detection of postoperative infection (PPV). Our study goal was to estimate the PPV after cesarean birth using hospital's International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes. Because earlier studies had low PPV for infection from antibiotic medication administration records, if each prescription had a corresponding diagnosis code, infections must have been listed for presumptive diagnoses (e.g., redness), not literally infection. Our cohort of obstetrical patients was unique for scientific investigation in that the vast majority developing postoperative infection were evaluated postoperatively by the same (surgical) department. MethodsThe population studied were all patients undergoing cesarean delivery from October 2015 through March 2022 at the University of Iowa. The ICD-10-CM codes were obtained from any type of encounter in the health record (e.g., clinic visit or emergency room). The hospital's quality improvement daily surveillance program followed National Healthcare Safety Network (NHSN) definitions. ResultsThe 147 cases studied were 2.9 % of the 5006 cesarean deliveries performed. Every postoperative infection from the daily surveillance program was included among the 147 cases. There were 144 of these patients evaluated by an obstetrician on the date of the ICD-10 diagnosis code(s) detecting postoperative infection. The estimated positive predictive value was 99.3 % (143/144), lower 95 % confidence limit 96.8 %. ConclusionsTo optimize patient benefit and hospital return on investment, infection preventive measures should include operating room/specialty combinations with the most postoperative infections. Automated health record review is needed. Every ICD-10-CM code is based on a clinician's note and thus the clinician's specialty (department) is known from the hospital's diagnosis tables. Using diagnosis codes for 90-day postoperative infection from surgeons' notes, high positive predictive value can be obtained (e.g., for use by anesthesia departments).