The Accuracy of the FreeStyle Navigator Continuous Glucose Monitoring System in Children With Type 1 Diabetes

Jaeb Center for Health Research, Tampa, Florida, United States
Diabetes Care (Impact Factor: 8.42). 01/2007; 30(1):59-64. DOI: 10.2337/dc06-1407
Source: PubMed


To evaluate the accuracy and precision of the FreeStyle Navigator continuous glucose monitoring system in children with type 1 diabetes.
In 30 children with type 1 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.
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 < or = 20%.
The Navigator's accuracy does not yet approach the accuracy of current-generation 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.

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    • "In this series of experiments, as previously (12), the overnight glucose target was set at 6.6 mmol/L (120 mg/dL) to provide a margin of error. The median error of currently available real-time continuous glucose monitors is between 10 and 16% when plasma glucose levels are between 70 and 180 mg/dL (9,10,26,27). A sensor error overreading the plasma glucose by 33% would drive the true glucose to only 90 mg/dL. "
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