Effects of hemoglobin (Hb) E and HbD traits on measurements of glycated Hb (HbA1c) by 23 methods.

Journal ArticleGlycohemoglobin (GHB), reported as hemoglobin (Hb) A1c, is a marker of long-term glycemic control in patients with diabetes and is directly related to risk for diabetic complications. HbE and HbDare the second and fourth most common Hb variants worldwide. We investigated the accuracy of HbA1c measurement in the presence of HbE and/or HbD traits

Multicenter assessment of a hemoglobin A1c point-of-care device for diagnosis of diabetes mellitus.

ObjectiveA multisite investigation compared the analytical performance of a point-of-care (POC) HbA1c device with multiple commonly used HbA1c laboratory methods and an NGSP (National Glycohemoglobin Standardization Program) reference method.Research design and methodsThe Afinion AS100 POC device analyzed HbA1c using 618 EDTA whole blood excess patient specimens with clinically indicated HbA1c testing. Results were compared to measurements across five clinical laboratories and the NGSP reference method. Precision was evaluated over 8-10 consecutive days for low-, mid-, and high-range HbA1c specimens at all five sites.ResultsOver a wide range of HbA1c values (4.0%-15% HbA1c), 97.1% of the POC results and 94.5% of routine laboratory results fell within the target value of ±6% of the NGSP reference method results. The POC HbA1c results at 6.5% exhibited a total relative bias of -0.6% (-0.04% HbA1c) compared to the reference method while the aggregate of laboratory methods displayed a relative bias of -0.9% (-0.06% HbA1c). The total imprecision of the POC results ranged from 0.74-2.13% CV across the analytic measurement range compared to 0.81-3.23% CV for the routine laboratory methods.ConclusionsThe accuracy and precision of the Afinion POC HbA1c method was comparable to the laboratory HbA1c methods supporting the FDA's recent approval of the Afinion HbA1c Dx device for use in the diagnosis of diabetes

Multicenter assessment of a hemoglobin A1c point-of-care device for diagnosis of diabetes mellitus.

ObjectiveA multisite investigation compared the analytical performance of a point-of-care (POC) HbA1c device with multiple commonly used HbA1c laboratory methods and an NGSP (National Glycohemoglobin Standardization Program) reference method.Research design and methodsThe Afinion AS100 POC device analyzed HbA1c using 618 EDTA whole blood excess patient specimens with clinically indicated HbA1c testing. Results were compared to measurements across five clinical laboratories and the NGSP reference method. Precision was evaluated over 8-10 consecutive days for low-, mid-, and high-range HbA1c specimens at all five sites.ResultsOver a wide range of HbA1c values (4.0%-15% HbA1c), 97.1% of the POC results and 94.5% of routine laboratory results fell within the target value of ±6% of the NGSP reference method results. The POC HbA1c results at 6.5% exhibited a total relative bias of -0.6% (-0.04% HbA1c) compared to the reference method while the aggregate of laboratory methods displayed a relative bias of -0.9% (-0.06% HbA1c). The total imprecision of the POC results ranged from 0.74-2.13% CV across the analytic measurement range compared to 0.81-3.23% CV for the routine laboratory methods.ConclusionsThe accuracy and precision of the Afinion POC HbA1c method was comparable to the laboratory HbA1c methods supporting the FDA's recent approval of the Afinion HbA1c Dx device for use in the diagnosis of diabetes

Global standardization of glycated hemoglobin measurement: the position of the IFCC Working Group

The measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c measurement. The main achievements can be summarized as follows: a) a reference measurement procedure has been established with purified primary calibrators; b) a network of reference laboratories has been developed worldwide; and c) work has begun on implementation of traceability to the IFCC reference system. The IFCC WG-HbA1c recognizes the recommendation of the IFCC-IUPAC Committee on Nomenclature, Properties and Units that the analyte measured by the IFCC reference measurement procedure has been defined as beta N1-deoxyfructosyl-hemoglobin and that the recommended measurement units are mmol/mol. The IFCC WG-HbA1c recommends maintaining the use of the name HbA1c in clinical practice