Spencer DH, et al. Clinical Chemistry 2011. 57:344-6. The authors in this study measured A1c 28 or more days before and 14-21 days after transfusion. They found that transfusion of one or more units reduced A1c by 0.83% in all subjects. When they looked at subjects with an A1c of 7% or greater prior to transfusion, the decrease in A1c was almost 2%. The mechanism was presumably dilution of the subjects' more glycated blood with less glycated donor blood. I don't know when A1c is accurate after Xfusion. It's more than 3 weeks. Our hospital is pushing for a CPOE rule that would prevent ordering A1c within 60 days of a transfusion. The rationale for waiting seems reasonable; I suspect the suggested "60 day" interval is based on the expected avg. in vivo lifespan of donor RBCs.
Spencer DH, et al. Clinical Chemistry 2011. 57:344-6. The authors in this study measured A1c 28 or more days before and 14-21 days after transfusion. They found that transfusion of one or more units reduced A1c by 0.83% in all subjects. When they looked at subjects with an A1c of 7% or greater prior to transfusion, the decrease in A1c was almost 2%. The mechanism was presumably dilution of the subjects' more glycated blood with less glycated donor blood. I don't know when A1c is accurate after Xfusion. It's more than 3 weeks. Our hospital is pushing for a CPOE rule that would prevent ordering A1c within 60 days of a transfusion. The rationale for waiting seems reasonable; I suspect the suggested "60 day" interval is based on the expected avg. in vivo lifespan of donor RBCs.