Red Blood Cell Transfusion: A Clinical Practice Guideline From the AABB*

cells (RBCs) are transfused annually worldwide, transfusion practices vary widely. The AABB (formerly, the American Association of Blood Banks) developed this guideline to provide clinical recom-mendations about hemoglobin concentration thresholds and other clinical variables that trigger RBC transfusions in hemodynamically stable adults and children. Methods: These guidelines are based on a systematic review of randomized clinical trials evaluating transfusion thresholds. We per-formed a literature search from 1950 to February 2011 with no language restrictions. We examined the proportion of patients who received any RBC transfusion and the number of RBC units trans-fused to describe the effect of restrictive transfusion strategies on RBC use. To determine the clinical consequences of restrictive trans-fusion strategies, we examined overall mortality, nonfatal myocar-dial infarction, cardiac events, pulmonary edema, stroke, thrombo