Accuracy of blood sugar meter questioned

NEW YORK (Reuters Health) - The FreeStyle Navigator continuous glucose (blood sugar) monitoring system is not as accurate as the current-generation home glucose meters, research suggests.

However, investigators believe that the device has the potential to become an important addition to the treatment of children with insulin-dependent type 1 diabetes. The FreeSyle Navigator uses a patch to monitor blood sugar, avoiding painful finger jabs.

"Direct reading, near-continuous, minimally invasive glucose sensors hold great promise for improving the care of patients with diabetes," researchers write in Diabetes Care. These sensors can provide both a measure of the current blood sugar level as well as trends in blood sugar levels, with alarms for high and low blood sugar.

Dr. Darrell M. Wilson and colleagues from the Jaeb Center for Health Research, Tampa, Florida, assessed the accuracy and precision of the FreeStyle Navigator in 30 children with diabetes.

The Navigator glucose values were compared with reference glucose values from blood samples collected in an inpatient clinical research center and measured in a central laboratory, and in an outpatient setting with a FreeStyle meter.

In a total of 1,811 inpatient sensor-reference pairs, the median absolute difference between these measurements was 17 mg/dL and the median relative absolute difference was 12 percent.

For 8,639 outpatient pairs, the median absolute difference and relative absolute difference was 20 mg/dL and 14 percent, respectively.

During the inpatient stays, the subjects simultaneously used two Navigator sensors resulting in 1,971 Navigator-Navigator pairs. The mean relative absolute difference between these simultaneous measurements was 13 percent.

Summing up, the researchers say that while the precision of the FreeStyle Navigator system does not yet match that of existing systems, it may eventually "become an important adjunct to treatment."

SOURCE: Diabetes Care January 2007.