User guide

high blood glucose can be obtained by setting the High Glucose Alert level lower. For example, setting the
High Glucose Alert at 190 mg/dL (10.6 mmol/L), instead of 250 mg/dL (13.8 mmol/L), increases the ability
to detect high blood glucose levels from 53% to 85% (see the following table).
Sometimes the Guardian RT will alert when the blood glucose levels are not high. When the Guardian RT
High Alert was set at 250 mg/dL (13.8 mmol/L) in this study, 7.2% of the results were considered false
alerts (actual blood glucose values are less than 225 mg/dL (12.5 mmol/L)). This percentage may be
exaggerated because blood glucose may be rising when the Guardian RT alerts. The table below shows the
percent of High Glucose readings correctly identified by the Guardian RT for specific settings.
Guardian RT High Alert
Setting (mg/dL)
Guardian RT High Alert
Setting (mmol/L)
True Alert Rate* False Alert Rate**
190 10.6 85% 64%
200 11.1 81% 58%
225 12.5 67% 40%
250 13.8 53% 25%
* True Alert Rates are the % of times when the glucose level was at or above the alert setting and the alert
sounded.
** False Alerts Rates are the % of times when the Guardian RT Sensor alarmed but the blood glucose level
was lower than the alert setting.
Decreasing the High Alert settings will improve the ability to detect high blood glucose events, but it will
also increase the frequency of Guardian RT false alerts for blood glucose levels not above the target value.
You should consider this trade-off between the improved ability to detect true high blood glucose versus
the increased number of false alerts when setting the high alert threshold.
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.
Sensor accuracy 141
Appendix A