Diabetes Associations Announce Global Standards for Hemoglobin A1c Measurement

The proposed new procedure based, for the first time on reference materials, would result in lower HbA1c percentage values than clinicians are used to seeing because of the higher specificity of the method, the statement claimed.

Hemoglobin A1c levels will be reported as both the percentages typically used in the United States under the National Glycohemoglobin Standardization Program (NGSP) and in the International System of Units (SI units) of mmol/mol under the new International Federation of Clinical Chemistry and Laboratory Medicine (IFCC; Milan, Italy) scheme. The consensus statement appeared in the June 2, 2010, online edition of the journal Diabetes Care.

Point-of-care (POC) HbA1c systems as well as laboratories need to be part of the quality control changes, noted statement authors Ragnar Hanas, MD, PhD, of Uddevalla Hospital in (Uddevalla, Sweden) and Garry John, PhD, of the Norfolk and Norwich University Hospital (Norwich, UK).

All standardization systems currently used lack primary and secondary reference materials that ensure that a patient would have comparable results from any laboratory, Dr. Hanas and Dr. John explained.

The new IFCC procedure was created to remedy this problem. It includes a specific incubation process to quantify and separate glycosylated and nonglycosylated hexapeptides on the hemoglobin molecule using mass spectrometry or capillary electrophoresis; isolation of pure HbA1c and pure nonglycosylated hemoglobin from human blood and mixed in well-defined proportions to produce a certified primary reference material set for calibrating the primary reference measurement system; assigning primary reference measurement system values to secondary reference materials (whole blood), then used by the manufacturers to calibrate their instruments.

Implementation of this method is ongoing, with a laboratory network established to put the new system into practice and maintain it, according to the statement.

This reference system "represents the only valid anchor to implement standardization," but determining how to present the numbers has been the subject of considerable debate, the consensus statement authors wrote.

The conclusions represented a consensus among the American Diabetes Association (Alexandria, VA, USA), the European Association for the Study of Diabetes (EASD; Düsseldorf, Germany) the International Diabetes Federation, (Brussels, Belgium) the IFCC, and the International Society for Pediatric and Adolescent Diabetes (ISPAD; Berlin Germany).

Related Links:
National Glycohemoglobin Standardization Program
International Federation of Clinical Chemistry and Laboratory Medicine
Norwich University Hospital
American Diabetes Association
European Association for the Study of Diabetes
International Diabetes Federation
International Society for Pediatric and Adolescent Diabetes