Adjusted change in Hb (with 95% CI) and HbA percent per day from the pretransfusion value across all 3 transfusion events, stratified by phlebotomy time point and adjusted for the number of units transfused. (A-B) Hb increment 2 hours after transfusion (34 pre-to-post deltas based on 14 unique participants), 24 hours after transfusion (29 pre-to-post deltas based on 14 unique participants), and 2 weeks after transfusion (55 pre-to-post deltas based on 24 unique participants) are shown by study arm (A) and by PS-PE surface content (B). No significant differences were noted by study arm at 2 hours or 2 weeks after transfusion but was significant at 24 hours after transfusion (2.22 vs 3.23 g/dL; P = .007). Transfusion episodes classified as PS-PE high had significantly smaller Hb increments at both 24 hours and 2 weeks after transfusion, compared to PS-PE mixed and low transfusion events (24 hours, 2.38 vs 2.82 vs 2.89 g/dL [P = .02]; 2 weeks, 0.59 vs 0.89. vs 1.04 g/dL [P = .04]). (C-D) The adjusted mean decrement in HbA percent per day (with 95% CI) across all 3 transfusion events during the first 2 weeks after transfusion, the second 2 weeks after transfusion, and overall (change between exchanges) are shown by study arm (C) and during the first 2 weeks and second 2 weeks post-transfusion by PS-PE surface content (D). Transfusion-specific decrement per day from 2 hours to 2 weeks after transfusion is based on 28 transfusions involving 13 unique patients. Transfusion-specific decrement per day from 2 weeks to before the next transfusion included 19 total assessments from 11 unique patients. The overall change in HbA percent per day by study arm was –0.24% for those receiving ≤10-day units and –0.14% for those receiving ≥30-day units (P = .3). There were no significant differences in the change in HbA percent per day by study arm or PS-PE, but PS-PE high and ≥30-day units had greater decrements in the first 2 weeks.