Accuracy of Newer-Generation Home Blood Glucose Meters in a Diabetes Research in Children Network (DirecNet) Inpatient Exercise Study

Abstract

The objective of this study was to assess how the accuracy of the FreeStyle Flash (Abbott Diabetes Care, Alameda, CA) meter compares with that of the One Touch Ultra (Lifescan, Milpitas, CA) home glucose meter (HGM). Fifty children with type 1 diabetes (T1D), 10-17 years old, were admitted for two separate 24-h periods to assess the effect of exercise on subsequent nocturnal hypoglycemia. Resulting data were used in a preplanned analysis of the accuracy of the Ultra and FreeStyle HGMs. Glucose levels were measured throughout the day and night and every 15-20 min during a standardized exercise protocol. Reference samples were assayed in a central laboratory using a hexokinase enzymatic method. These reference glucose measurements were paired with HGM values from venous blood obtained within +/- 5 min. The median relative absolute difference was 5% for both the Ultra and FreeStyle HGMs, and the percentages of pairs meeting the International Organisation for Standardization criteria were 99% and 98%, respectively. The FreeStyle tended to read slightly higher than the reference method (median difference = +3 mg/dL; P < 0.001), and there was trend in this direction for the Ultra (median difference = +2 mg/dL, P = 0.15). Sensitivities for detection of hypoglycemia (reference < or = 60 and HGM < or = 70 mg/dL) were 96% and 100% for the Ultra and FreeStyle, respectively, and corresponding false-positive rates were both 5%. In a controlled clinical setting using venous blood samples, both the Ultra and FreeStyle meters demonstrated a high degree of accuracy compared with the laboratory reference over a broad range of glucose concentrations in children with T1D.