Another Step Toward Standardization of Methods for Measuring Hemoglobin A1c

Abstract

In this issue, Kobold et al. describe an exciting new Reference Method for hemoglobin A1c developed by the International Federation of Clinical Chemistry Working Group on Hemoglobin A1c (1). To our knowledge, this method represents the first time mass spectrometry has been applied to a protein of clinical interest in a high-level (Definitive) Reference Method. Measurements of hemoglobin A1c (or, alternatively, of glycohemoglobin) are increasingly important in the monitoring of glucose control in patients with diabetes. The test’s importance became especially prominent after the publication of the Diabetes Control and Complications Trial (DCCT), which demonstrated the importance of control of blood glucose in the prevention or delay of the complications of diabetes (2). The test has recently caught the eye of the US government as one that is underutilized (3). Thus, it is not much surprise that both an AACC Subcommittee, which has evolved into the National Glycohemoglobin Standardization Program (NGSP) (4), and an IFCC Working Group, from which Kobold’s report emanates, have been addressing glycohemoglobin standardization over the past several years. Several other editorials in this Journal (5)(6)(7) have commented on important papers relating to glycohemoglobin over the years. Because the most recent of these, one by Miedema, gave such a good overview of the chemistry of glucose addition to hemoglobin, nomenclature, and analytical methodologies, we will not repeat this information here. Instead, our discussion will focus on the relative importance of accurate results, harmonious results, and the preservation of reference values with which clinicians are familiar. The application of knowledge gained in any large clinical research study to routine medical practice is frequently a challenge. Of particular interest to clinical laboratorians are studies in which major therapeutic decisions are based on a clinical laboratory result. The scale used to measure the …