Product Info

The false alert rate is important because it is necessary that users be correctly
notified when their BG is low (or high) so that they can correct the low (or high)
BG. A low false alert rate indicates that when the CGM system says that their
glucose values are, or will reach a specified threshold, the user’s BG is likely to be
at or approaching that threshold.
For example, per the following table, the high glucose threshold alerts would have
incorrectly indicated that the user was above (i.e. threshold only), or predicted to
reach above the threshold (i.e. predictive only), or both (threshold and predictive)
6.30%, 29.5%, or 22% of the time within 30 minutes (or 7.2%, 33.1%, or 24.6% of
the time within 15 minutes) when the user had BG less than 180 mg/dL for a
sensor inserted in the abdomen.
Table C-2: Glucose FALSE Alert Performance using Calibration every 12 hours
Glucose FALSE Alert Rate
mg/dL Insertion Site Threshold Only Predictive Only Threshold and Predictive
30 min 15 min 30 min 15 min 30 min 15 min
50 Abdomen 75.0% 75.0% 84.8% 87.7% 81.8% 83.8%
Arm 63.2% 63.2% 78.1% 83.3% 73.9% 77.6%
60 Abdomen 46.5% 48.1% 59.3% 62.9% 53.8% 56.6%
Arm 31.0% 32.2% 52.5% 54.4% 44.9% 46.5%
70 Abdomen 33.1% 33.1% 47.3% 52.3% 41.7% 44.8%
Arm 22.6% 24.7% 42.6% 45.5% 34.4% 37.0%
80 Abdomen 30.7% 30.7% 42.2% 48.9% 37.8% 41.8%
Arm 22.5% 23.6% 40.1% 47.0% 33.5% 38.1%
90 Abdomen 24.9% 25.6% 36.0% 41.5% 32.1% 35.7%
Arm 25.1% 25.1% 31.0% 36.8% 28.7% 32.0%
180 Abdomen 6.30% 7.20% 29.5% 33.1% 22.0% 24.6%
Arm 7.10% 7.10% 32.0% 36.8% 23.5% 26.3%
220 Abdomen 8.10% 8.10% 31.1% 33.7% 23.4% 25.2%
Arm 7.80% 7.80% 34.3% 37.8% 25.5% 27.8%
250 Abdomen 9.80% 9.80% 36.0% 39.9% 27.5% 30.2%
Arm 8.60% 8.60% 38.0% 40.2% 28.9% 30.4%
300 Abdomen 18.8% 18.8% 42.2% 46.0% 34.6% 37.3%
Arm 18.1% 19.4% 48.3% 50.3% 38.8% 40.7%
Glucose Correct Detection Rate
Glucose Correct Detection Rate is the rate that the device alerted when it should
have alerted. For example, the BG was below the hypoglycemic threshold, or
above the hyperglycemic threshold, and the device sounded an alert.
346 Chapter 17