The investigators first randomized clinical trial (RCT) of iron supplementation of critically ill surgical patients compared enteral ferrous sulfate 325 mg thrice daily to placebo (NCT00450177). Although a significant reduction in pRBCs transfusion requirement for the iron group was observed, low injury severity, intolerance of enteral medications, and a predominance of traumatic brain injury limited generalizability. In a second multicenter RCT, the investigators compared intravenous iron sucrose 100 mg thrice weekly to placebo among critically ill trauma patients (NCT01180894). Iron supplementation at this dose increased the TSAT only marginally (and not above the normal range) and increased the serum ferritin concentration significantly; however, there was no effect on IDE, anemia, or pRBCs transfusion requirement. In no instance did iron supplementation increase the risk of infection, despite a relatively high incidence of marked hyperferritinemia (serum ferritin concentration > 1,000 ng/mL) in the iron group.