Relative inaccuracy of the A1cNow in children with type 1 diabetes.
The Diabetes Control and Complications Trial (DCCT) confirmed the importance of tight glucose control in limiting the development of microvascular complications and established a standard for measuring A1C levels using high-performance liquid chromatography (HPLC) (1). Several studies demonstrated the benefit of rapid A1C testing in the clinic while face-to-face with the patient/family (2–4). The DCA2000 Analyzer (Bayer, Tarrytown, NY) uses an immunoassay method certified by the National Glycohemoglobin Standardization Program (NGSP) (5). It is frequently used to provide a rapid (6 min) A1C result, enhancing the ability to optimize therapy in a timely fashion. We recently reported that the DCA2000 was highly correlated with an HPLC reference (the DCCT standard) (r 0.94, P 0.001), although there was a slight bias with DCA2000 values being, on average, 0.2% higher than laboratory values (6). The A1cNow (Metrika, Sunnyvale, CA) was developed as a single-use, disposable test for measuring A1C at home. It is small, about the size of a pager, requires one drop of blood, and uses an immunoassay. Results are displayed in 8 min. However, there has been only one published study (7) to date assessing the accuracy of the A1cNow, and that study did not compare A1cNow values to the DCA2000. Furthermore, older generation A1cNow devices that were not NGSP certified were used in that study. We therefore designed the current study to compare the accuracy of updated, NGSP-certified A1cNow devices and corresponding DCA2000 levels with the DCCT/Epidemiology of Diabetes Interventions and Complications (EDIC) Study laboratory reference values when used at home and during a clinic visit in children with type 1 diabetes.