Red Cell Transfusion Decreases Hemoglobin A1c in Patients with Diabetes

[摘要] To the Editor:Hemoglobin A1c (Hb A1c)1 is a mainstay of diabetes diagnosis and management that allows clinicians to estimate the recent mean blood glucose concentration of a patient. Glycation of hemoglobin is an irreversible, nonenzymatic process that depends on the glucose concentration in red blood cells (RBCs), and Hb A1c represents the integrated glucose concentration in RBCs over their life span.RBC transfusion can complicate the interpretation of Hb A1c values in diabetic patients because it introduces hemoglobin molecules exposed to glucose concentrations that may have been different from the glucose concentrations in the diabetic transfusion recipient. The potential effect of transfusion on Hb A1c has been recognized for some time, but opinions on the direction of the effect are contradictory. Data from the older literature (1–3) suggest that the high concentration of glucose in RBC storage medium promotes glycation and causes Hb A1c values to increase over time, which would predict that Hb A1c might increase in transfused patients. This concept has been stated in a recent review article (4) and on consumer Web sites, such as Lab Tests Online (http://labtestsonline.org/understanding/analytes/a1c/test.html); however, a recent case in which a pathology resident was contacted to explain a patient's Hb A1c value decreasing from 7.4% to 5.4% in 3 days after the patient …

[学科分类] 过敏症与临床免疫学