FCGR1A and systemic inflammatory response syndrome: Monocyte CD64 expression did not differ among subgroups; however, there was significant variation with time (p = 0.0016), with the sepsis group expressing significantly higher CD64 at the 7 h time point compared to the preop value, and at the 7 hours and day 1 timepoint compared to the preop value in the SIRS and non-complicated groups.