Diagnostic accuracy of C-reactive protein for intraabdominal infections after colorectal resections

Intraabdominal infections are caused mainly by anastomotic leaks and represent a serious complication. Diagnosis is usually made when patients become critically ill. Though inflammatory markers, including C-reactive protein (CRP) and white blood count (WBC), may contribute to an early diagnosis, their clinical roles remain unclear. The diagnostic accuracy of continuous tests depends on the choice of cut-off values. We analyzed the diagnostic accuracy of serial CRP and WBC measurements to detect infectious complications after colorectal resections.

The CRP and WBC were routinely measured postoperatively in 231 consecutive patients undergoing colorectal resection. Clinical outcome was registered with regard to postoperative complications. The diagnostic accuracy of CRP and WBC was analyzed by receiver operating characteristics (ROC) curve analysis with intra- and extraabdominal infectious complications as the outcome.

Increased CRP levels on postoperative day (POD) 3 were associated with intraabdominal infections. The best cut-off value was 190 (sensitivity, 0.82; specificity, 0.73). The area under the ROC curve was 0.82. On POD 5 and 7, the diagnostic accuracy of CRP was similar.

Serial CRP measurements are helpful for detecting intraabdominal infections after colorectal resection. Persistently elevated CRP values after POD 3 should be investigated for intraabdominal infection.