Abbott FreeStyle Libre 2 User Manual page 210

For example, the Adult study found that for a High Glucose alarm level set to 200 mg/dL:
99.2% of the time a high glucose alarm was received when blood glucose was indeed above the
alarm level but 0.8% of the time a high glucose alarm was received when blood glucose wasn't
actually above the alarm level.
97.1% of the time blood glucose was above the alarm level and a high glucose alarm was
appropriately issued but 2.9% of the time the glucose event was missed and no alarm was issued.
Table 5c: High Glucose Alarm Performance (Adult; n=144)
High Glucose
Alarm level
Number of
(mg/dL)
Events (n)
120 105544
140 93574
180
74290
200
66039
220
57549
240
48733
300
21512
Alarm Rate
True Alarm False Alarm
Rate (%) Rate (%)
99.1 0.9
99.1 0.9
99.2 0.8
99.2 0.8
99.0 1.0
98.4 1.6
96.3 3.7
Detection Rate
Correct
Number of
Detection
Events (n)
Rate (%)
11417 98.2
10152 98.1
97.8
8080
97.1
7269
96.9
6390
95.6
5550
90.0
2672
Missed
Detection
Rate (%)
1.8
1.9
2.2
2.9
3.1
4.4
10.0
204