Product Info

True Threshold Hyperglycemic alert ratealerted when the CGM read that the user
was above the high threshold and the user’s blood glucose was actually above
that high threshold.
True Predictive Hypoglycemic alert ratealerted when the CGM predicted that the
user would reach below the low threshold and the user’s blood glucose was
actually below that low threshold within 15 or 30 minutes.
True Predictive Hyperglycemic alert rate alerted when the CGM predicted that
the user would reach above the high threshold and the user’s blood glucose was
actually above that high threshold within 15 or 30 min.
The true alert rate is important because it is necessary that users be notified when
their blood glucose is low (or high) so that they can correct the low (or high)
blood glucose. A high true alert rate indicates that when the CGM says that their
glucose values are, or will reach a specified threshold, the user’s blood glucose is
likely to be at or approaching that threshold.
For example, per the following table, when wearing the sensor in the Buttocks, the
low glucose alerts would have correctly indicated that the user was below (i.e.
threshold only), or predicted to reach below the threshold (i.e. predictive only) or
both (predictive and threshold) 100%, 40%, or 57.1 % of the time within 30
minutes (or 100%, 40% or 57.1% of the time within 15 minutes) when the user had
blood glucose values lower than 70 mg/dL.
Table I-1. Glucose TRUE Alert Performance using Calibration every 12 hours
Glucose TRUE Alert Rate
mg/dL Insertion Site Threshold Only Predictive Only Threshold & Predictive
30 min 15 min 30 min 15 min 30 min 15 min
50 Abdomen N/A* N/A* N/A* N/A* N/A* N/A*
Buttock 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
60 Abdomen N/A* N/A* 0.0% 0.0% 0.0% 0.0%
Buttock 100.0% 100.0% 25.0% 25.0% 40.0% 40.0%
70 Abdomen 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Buttock 100.0% 100.0% 40.0% 40.0% 57.1% 57.1%
80 Abdomen 25.0% 25.0% 16.7% 0.0% 20.0% 10.0%
Buttock 40.0% 40.0% 33.3% 22.2% 35.7% 28.6%
90 Abdomen 50.0% 50.0% 50.0% 33.3% 50.0% 40.0%
Buttock 100.0% 100.0% 81.8% 63.6% 88.9% 77.8%
180 Abdomen 100.0% 100.0% 80.0% 70.0% 85.7% 78.6%
Buttock 89.7% 89.7% 84.8% 81.8% 85.7% 83.9%
394 Chapter 17