The accuracy of the FreeStyle navigator continuous glucose monitoring system in children with type 1 diabetes

OBJECTIVE - To evaluate the accuracy and precision of the FreeStyle Navigator continuous glucose monitoring system in children with type I diabetes. RESEARCH DESIGN AND METHODS - in 30 children with type I diabetes (mean age 11.2 +/- 4.1 years), the Navigator glucose values were compared with reference serum glucose values of blood samples obtained in an inpatient clinical research center and measured in a central laboratory using a hexokinase enzymatic method and in an outpatient setting with a FreeStyle meter. Median absolute difference (AD) and median relative absolute difference (RAD) were computed for sensor-reference and sensor-sensor pairs. RESULTS - The median AD and RAD were 17 mg/dl and 12%, respectively, for 1,811 inpatient sensor-reference pairs and 20 mg/dl and 14%, respectively, for 8,639 outpatient pairs. The median RAD between two simultaneous Navigator measurements (n = 1,971) was 13%, Ninety-one percent of sensors in the inpatient setting and 81% of sensors in the outpatient setting had a median RAD <= 20%. CONCLUSIONS - The Navigator's accuracy does not yet approach the accuracy of currentgeneration home glucose meters, but it is sufficient to believe that the device has the potential to be an important adjunct to treatment of youth with type 1 diabetes.