title: Whole Blood Donation Affects the Interpretation of Hemoglobin A1c.
abstract: BACKGROUND
  Several factors, including changed dynamics of erythrocyte formation and degradation, can influence the degree of hemoglobin A1c (HbA1c) formation thereby affecting its use in monitoring diabetes. This study determines the influence of whole blood donation on HbA1c in both non-diabetic blood donors and blood donors with type 2 diabetes.
  
  
  METHODS
  In this observational study, 23 non-diabetic blood donors and 21 blood donors with type 2 diabetes donated 475 mL whole blood and were followed prospectively for nine weeks. Each week blood samples were collected and analyzed for changes in HbA1c using three secondary reference measurement procedures.
  
  
  RESULTS
  Twelve non-diabetic blood donors (52.2%) and 10 (58.8%) blood donors with type 2 diabetes had a significant reduction in HbA1c following blood donation (reduction >-4.28%, P < 0.05). All non-diabetic blood donors with a normal ferritin concentration predonation had a significant reduction in HbA1c. In the non-diabetic group the maximum reduction was -11.9%, in the type 2 diabetes group -12.0%. When eligible to donate again, 52.2% of the non-diabetic blood donors and 41.2% of the blood donors with type 2 diabetes had HbA1c concentrations significantly lower compared to their predonation concentration (reduction >-4.28%, P < 0.05).
  
  
  CONCLUSIONS
  Patients with type 2 diabetes contributing to whole blood donation programs can be at risk of falsely lowered HbA1c. This could lead to a wrong interpretation of their glycemic control by their general practitioner or internist.
authors.affiliation: Sanquin Blood Bank Division, Zwolle, the Netherlands.
authors.forename: Angelique
authors.identifier: http://orcid.org/0000-0003-2564-2280
authors.initials: A
authors.lastname: Dijkstra
authors.affiliation: Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands.|European Reference Laboratory for Glycohemoglobin, Isala Hospital, Zwolle, the Netherlands.
authors.forename: Erna
authors.initials: E
authors.lastname: Lenters-Westra
authors.affiliation: Department Donor Studies, Sanquin, Amsterdam, the Netherlands.|Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: de Kort
authors.affiliation: Department Medical Donor Affairs, Sanquin Blood Bank Division, Amsterdam, the Netherlands.
authors.forename: Arlinke G
authors.initials: AG
authors.lastname: Bokhorst
authors.affiliation: Department of Internal Medicine, Isala Hospital, Zwolle, the Netherlands.|Department of Internal Medicine, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: Henk J G
authors.initials: HJ
authors.lastname: Bilo
authors.affiliation: Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands.|European Reference Laboratory for Glycohemoglobin, Isala Hospital, Zwolle, the Netherlands.
authors.forename: Robbert J
authors.initials: RJ
authors.lastname: Slingerland
authors.affiliation: Department of Clinical Chemistry, Isala Hospital, Zwolle, the Netherlands.
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Vos
mesh_terms: D000368:Aged; D001782:Blood Donors; D001798:Blood Proteins / Q000032:analysis; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D004920:Erythropoiesis; D005260:Female; D005293:Ferritins / Q000097:blood; D005544:Forecasting; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008687:Metformin / Q000627:therapeutic use; D008875:Middle Aged; D011446:Prospective Studies; D014815:Vitamins / Q000097:blood
chemical_list: D001798:Blood Proteins; D005293:Ferritins; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin; D014815:Vitamins; C517652:hemoglobin A1c protein, human