Sensor Life - Dexcom G4 User Manual

Table 8. Sensor Stability (Accuracy
Number of
Day of
Study paired CGM-
2
Wear
Original
Day 1
Software
505
Original
Day 4
Software
505
Original
Day 7
Software
505
1
CGM readings are within 40 to 400 mg/dL, inclusive.
2
Both sets of study data are presented and are labeled as
Sensor Stability
Sensors can be worn for up to 7 days. To verify sensor performance over time, 72 subjects were evaluated
with the Original System across the 7-day wear period while 50 subjects were evaluated with the
505 System across the 7-day wear period. Performance was estimated by calculating the percentage of
System readings within 15 mg/dL or 15%, 20 mg/dL or 20%, 30 mg/dL or 30% , 40 mg/dL or 40% and
greater than 40 mg/dL or 40% of the YSI values at the beginning (Day 1), middle (Day 4) and end (Day 7) of
the System lifecycle. The average and median of the absolute percent differences are included in Table 8
showing consistent accuracy and sensor stability over the 7-day life of the sensor.
Precision of System Readings
In the Original Study, 36 subjects wore two Systems. This was to look at how similarly two Systems
function on the same subject (sensor precision). Precision was evaluated by comparing the glucose
readings from the two Systems worn on the same subject at the same time. Results showed that System
readings from the two sensors generally agreed with each other within 9% (absolute percent difference) with
a 7% coefficient of variation. Only one System was worn in the
not collected in this study.

Sensor Life

Sensors may be worn for up to 7 days (168 hours). To estimate how long a sensor will work over 7 days,
108 sensors were evaluated with the
sensor provided. Ninety-four percent (94%) of the sensors lasted until Day 7 (145-168 hours). There were 6
(6%) sensors that ended early, four of which lasted more than 3 days.
For the Software 505 Study, 51 sensors were evaluated to determine how many days/hours of readings
each sensor provided. Ninety-eight percent (98%) of the sensors lasted until Day 7 (145-168 hours). There was
1 (2%) sensor that ended early, which lasted until day 5 of the sensor wear.
1
Mean Absolute
Percent
YSI Differences
3023 16.7%
680 10.7%
3108 11.4%
777 8.0%
3021 11.9%
806 8.5%
Original Study to determine how many days/hours of readings each
over Time)
Median Percent
Absolute within
Percent 15/15%
Differences YSI
13.2% 59%
7.9% 77%
8.2% 77%
6.4% 89%
8.9% 76%
7.2% 90%
Original (SW10050) or
Software 505
Percent Percent
within within
20/20% 30/30%
YSI YSI 40/40% YSI
71% 86%
84% 96%
87% 95%
96% 99%
87% 95%
97% 99%
Software 505 (SW10505).
Software
Study so precision data was
Percent
greater
than
6%
2%
2%
0%
2%
0%