Neutrophil CD64 as a marker for postoperative infection: a pilot study

The aim of this pilot study was to evaluate the clinical utility of quantitative CD64 measurements to differentiate between systemic inflammation in response to surgical trauma and postoperative bacterial infection. In a consecutive series of 153 patients undergoing elective vascular surgery, peripheral venous blood samples were taken preoperatively on admission and postoperatively during the first 24h. The samples were analysed for C-reactive protein (CRP), total leucocyte counts (white blood cell (WBC)), serum procalcitonin (PCT) and neutrophil CD64 expression. Of the 153 patients, the focus is on those with (1) postoperative infection alone (group 1; n=1 4); (2) pre- and postoperative infection (group 2; n=6); and (3) postoperative fever with no other signs of infection (group 3; n=29). In group 1, all four markers were significantly increased in the 24h after surgery: CD64 (p=0.001), CRP (p=0.001), WBC (p=0.002) and PCT (p=0.012); in group 2, there was no significant difference in the CD64 (p=0.116), WBC (p=0.249) and PCT (p=0.138) values, whereas a marginal significance was shown for CRP (p=0.046); and the results for group 3 were similar to those of group 1. This pilot study suggests that the role of neutrophil CD64 measurements in facilitating the diagnosis of early postoperative infection merits further investigation.