User Manual

Performance Characteristics 93
An analysis of the mean percentage of Absolute Relative Error (ARE %) and standard deviations, across
12-hour increments of wear periods, appears in Table 5.8 below. Both data sets are pooled together in
this data.
Table 5.8: Performance As a Function of Sensor-Insertion Time
The median Sensor life from Data Sets A and B were 57.5 hours and 72.9 hours, respectively. Twenty-one
of the Sensors operated for 72 hours, while the others were removed for a variety of reasons, most often
because of calibration errors.
The percentage of Guardian RT readings within 20 mg/dl and 30 mg/dl of YSI readings from 40-80 mg/dl
(Table 5.9), and the percentage of readings within 20% and 30% of YSI readings from 81-120 mg/dl
(Table 5.10), was analyzed according to time after Sensor insertion and according to the glucose-
concentration range (as determined by the YSI analyzer).
Table 5.9
Hours From
Insertion
Mean ARE (%) Std. Dev.
0-12 hrs 24.84 20.04
12-24 hrs 19.66 16.17
24-36 hrs 16.43 15.62
36-48 hrs 18.23 19.27
48-60 hrs 16.59 14.25
>60 hrs 22.95 23.51
Percentage of Guardian RT values within
20 mg/dl of YSI laboratory readings
Percentage of Guardian RT values within
30 mg/dl of YSI laboratory readings
Glucose
Range
(mg/dl)
During first 60 hours
of Sensor wear
After 60 hours
of Sensor wear
During first 60
hours of Sensor
wear
After 60 hours of
Sensor wear
40-80 62-82% 39% 78-91% 67%