Nomenclature. Standardized, well-defined nomenclature is essential for effective communication of the results of basic and clinical research on glucosylated hemoglobin in diabetes. Proper use of the terms defined in the Appendix should eliminate some problems and confusion in the literature. Test procedures. A wide variety of assays and procedures is available for measuring glucosylated hemoglobin. When properly performed, suitable precision, long-term reproducibility, and correlation with glycemic control is achievable with each of the three basic types of assays, i.e., those based on charge or structural differences or on chemical analysis of hemoglobin. No single assay procedure appears to be clearly superior to others at this time, and excellent correlations are obtained among the results of each of the assay procedures. Thus, the selection of a method should be based on the expertise, equipment, and special needs of the individual laboratory. Assay precision and long-term reproducibility. Problems with assay precision and reproducibility in the past have created undue skepticism about the clinical utility of glucosylated hemoglobin measurements. At present, intra- and interassay coefficients of variation of <5% are attainable, and should be achieved in any laboratory performing these measurements. Interference by pre-A(Ic) is a major source of variation in the determination of HbA(I) by ion exchange or by electrophoretic methods, and should be removed before these assays. Assay standards. The development of a stable reference standard, useful in all types of glucosylated hemoglobin assays, is important to ensure long-term assay reproducibility and to facilitate the comparison of results between laboratories. The development of this standard should be identified as a major goal of future research.
Baynes, J. W., Bunn, H. F., Goldstein, D., Harris, M., Martin, D. B., Peterson, C., & Winterhalter, K. (1984). National diabetes data group: Report of the expert committee on glucosylated hemoglobin. Diabetes Care, 7(6), 602–606. https://doi.org/10.2337/diacare.7.6.602