User`s guide

Dexcom G4 User’s Guide | 129
11.2 DEVICE PERFORMANCE CHARACTERISTICS
The Dexcom G4 System (The System) uses a glucose sensor to continuously
measure and monitor your glucose levels. The sensor is “calibrated” using a
commercially available blood glucose meter (OpenChoice), once calibrated,
the System reports glucose readings up to every 5 minutes. The System was
evaluated in a clinical study, CGM readings were compared to blood glucose
values to assess its performance and how well the System readings compare
to a laboratory test method that measures blood glucose values. Additionally,
patients performed self-monitoring blood glucose meter tests at home to
assess the System performance in real use environment.
Although the performance characteristics of the System are presented in the
following, there is no commonly accepted statistical approach for capturing
performance of continuous glucose monitors, such as the System.
Clinical Study Overview
The System performance was evaluated in a prospective clinical study, 21
participants were enrolled. All participants had Type 1 or Type 2 diabetes
mellitus, and required insulin to manage their diabetes. About 90.5% of
participants had Type 1 diabetes and about 9.5% had Type 2 diabetes. The
study included subjects greater than 18 years old in age.
Participants used the System for seven days; each participant wore 2 sensors.
Sensors were calibrated approximately once every 12 hours, using the SMBG
values obtained from the Lifescan OneTouch Ultra2 meter. Throughout the
7-day wear period, the Sensor was calibrated with an average of 2 ngersticks
per day (approximately once every 12 hours).
All subjects participated in a controlled clinic environment on Day 1, Day
4, or Day 7 of the 7-day wear period. While using the System in the clinic,
participants had their blood glucose measured every 15 minutes with a
reliable laboratory method, the Yellow Springs Instrument 2300 STAT Plus
glucose analyzer. This instrument is referred to as the “YSI.” Readings from
the System were paired with YSI values in order to characterize how well the
HELPFUL HINT:
• We recommend that you review the information in this chapter with your
healthcare provider to understand how well the Dexcom G4 System
performs.