|
|
||||||||
General Clinical Chemistry |
1 Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN.
2 Biostatistics Center, the George Washington University, Rockville, MD.
3 Departments of Pathology and Anatomical Sciences and Child Health, University of Missouri, Columbia, MO.
4 Fairview University Medical Center, Minneapolis, MN.
aAddress correspondence to this author at: University of Minnesota, Department of Laboratory Medicine and Pathology, MMC 609, 420 Delaware St. S.E., Minneapolis, MN 55454. Fax 612-273-3489; e-mail steff001{at}umn.edu.
Background: Clinical trials require assays that provide consistent results during the course of a study. The hemoglobin A1c (HbA1c) assay, a measure of chronic glycemia, is critical to the study of diabetes control and complications.
Methods: The Diabetes Control and Complications Trial (DCCT) and its follow-up study, the Epidemiology of Diabetes Interventions and Complications (EDIC), required 20 years of consistent HbA1c results, measured by three different ion-exchange HPLC procedures. To maintain and document consistent HbA1c results measured in the DCCT and EDIC Central Biochemistry Laboratory, a backup laboratory used frozen hemolysates as long-term calibrators and a HPLC method with a single lot of Bio-Rex 70 resin.
Results: Over 20 years, long-term quality-control values have remained constant. Four studies of nondiabetic ranges produced nearly identical values [mean (SD), 5.1 (0.5)%, 4.9 (0.3)%, 5.0 (0.4)%, and 5.0 (0.3)%].
Conclusion: The overall consistency of the HbA1c assays during the 20-year course of the DCCT and EDIC has been critical in establishing the benefits of intensive therapy and in understanding the relationship between long-term glycemia and the development and progression of the complications of diabetes.
The following articles in journals at HighWire Press have cited this article:
![]() |
A. D. Paterson, B. N. Rutledge, P. A. Cleary, J. M. Lachin, R. S. Crow, and for the Diabetes Control and Complications Trial/E The Effect of Intensive Diabetes Treatment on Resting Heart Rate in Type 1 Diabetes: The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study Diabetes Care, August 1, 2007; 30(8): 2107 - 2112. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Selvin, C. M. Crainiceanu, F. L. Brancati, and J. Coresh Short-term Variability in Measures of Glycemia and Implications for the Classification of Diabetes Arch Intern Med, July 23, 2007; 167(14): 1545 - 1551. [Abstract] [Full Text] [PDF] |
||||
![]() |
The Diabetes Control and Complications Trial/Epide Long-Term Effect of Diabetes and Its Treatment on Cognitive Function N. Engl. J. Med., May 3, 2007; 356(18): 1842 - 1852. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. S. Kilpatrick, A. S. Rigby, and S. L. Atkin Variability in the Relationship between Mean Plasma Glucose and HbA1c: Implications for the Assessment of Glycemic Control Clin. Chem., May 1, 2007; 53(5): 897 - 901. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Fox, M. Dontchev, K. Ruedy, R. Beck, C. Kollman, L. Messer, J. Coffey, D. Wilson, E. Doyle, W. Tamborlane, et al. Relative Inaccuracy of the A1cNow in Children With Type 1 Diabetes Diabetes Care, January 1, 2007; 30(1): 135 - 137. [Full Text] [PDF] |
||||
![]() |
P. A. Cleary, T. J. Orchard, S. Genuth, N. D. Wong, R. Detrano, J.-Y. C. Backlund, B. Zinman, A. Jacobson, W. Sun, J. M. Lachin, et al. The Effect of Intensive Glycemic Treatment on Coronary Artery Calcification in Type 1 Diabetic Participants of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study Diabetes, December 1, 2006; 55(12): 3556 - 3565. [Abstract] [Full Text] [PDF] |
||||
Read all eLetters
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |