Abbott Freestyle PRT03831-xxx - Manual (Page 168)

18 Appendix B: Specifications
(con’t)
Stability of Sensor Calibration
FreeStyle Navigator system typically requires a calibration at 10, 12, 24 and 72 hours after insertion of
the sensor. This section presents information about the performance of the system by the 4 calibration
periods. The table (Table 6d) breaks each calibration period into smaller slots and summarizes the
difference from YSI in each slot. The data below demonstrates that there is little change in the system
performance within each period.
Table 6d. Distribution of the difference from the YSI in the different calibration windows
Calibration Period Percent Readings
Within 20%* of
the YSI
Percent Readings
Within 30%* of
the YSI
Percent Readings
Within 40%* of
the YSI
Cal 1
(typically occurs 10 hrs
after sensor insertion)
First Calibration Period
80 88 94
Cal 2
(typically occurs 12 hours
after sensor insertion)
First Third of Second
Calibration Period
83 94 98
Second Third of Second
Calibration Period
83 94 98
Final Third of Second
Calibration Period
84 95 98
Cal 3
(typically occurs 24 hours
after sensor insertion)
First Third of Third
Calibration Period
84 94 98
Second Third of Third
Calibration Period
80 92 97
Final Third of Third
Calibration Period
80 91 95
Cal 4
(typically occurs 72 hours
after sensor insertion)
First Quarter of Final
Calibration Period
86 93 96
Second Quarter of Final
Calibration Period
84 92 96
Third Quarter of Final
Calibration Period
80 93 98
Final Quarter of Final
Calibration Period
82 93 97
* The absolute difference from the YSI reading is measured in mg/dL if the YSI reading is at or below
75 mg/dL.
Sample Glucose Traces
The following figures show examples of glucose traces from the In-Clinic study. These traces are
representative examples of excellent, average and poor performance of the system. These traces show
an overlay of the continuous glucose readings from the FreeStyle Navigator system and the blood
glucose measurements made using the laboratory YSI reference. The blood glucose measurements that
were used to calibrate the system are marked with ‘x’ in the traces. Glucose results from the FreeStyle
Navigator system are shown using circles and the glucose results from the laboratory reference (YSI)
are shown using triangles. Time (hours since sensor insertion) is on the horizontal axis, and glucose
value in mg/dL is on the vertical axis.
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158 Section 18
Appendix B: Specifications