User Manual

92 Chapter 5
Guardian RT Sensor Performance and Calibration Stability As
a Function of Time
The Guardian RT Sensor may be worn for up to 3 days (72 hours) and must be calibrated at least twice a
day. Two sets of data, approximately equal in number, were collected during the clinical trial. One data
set was generated when the frequency of calibrations averaged 3.5 per day (Data Set A), and the other
averaged 5 times a day (Data Set B). During the study, a total of 38 Sensors were evaluated in 16
individuals.
As per the stratified Clarke Error Grid analysis above (Table 5.4), agreement between Guardian RT values
and YSI values tends to be poorer at low and high glucose concentrations when compared to other
concentration ranges.
Guardian RT performance in the hypoglycemic range, as a function of Sensor insertion time, is
characterized below. Results from the two different data sets are presented. The two populations were
separated according to the number of calibrations per day. Table 5.7 represents the percentage of Data
Points in the 40-80 mg/dl range that fell within 20 mg/dl. Data is presented in 12-hour increments.
Table 5.7
Data Set 0-12 hrs 12-24 hrs 24-36 hrs 36-48 hrs 48-60 hrs 60-72 hrs
A 78% 81% 73% 65% 56% 41%
B 67% 70% 93% 60% 75% 38%