User guide

The accuracy of the Guardian RT was also evaluated by calculating the percentage of Guardian RT
readings within 20% and within 30% of the blood glucose meter reading (or within 20 mg/dL (1.1 mmol/L)
in the low glucose range). Results are shown in the following table.
Plasma Glucose
Range (mg/dL)
Plasma Glucose
Range (mmol/L)
Number of Paired
Readings
Percent Within
20%
Percent Within
30%
Overall 2599 68% 82%
40-80* 2.2-4.4 360 51% ----
> 80-120 > 4.4-6.7 482 60% 77%
> 120-240 > 6.7-13.3 1055 74% 90%
> 240 > 13.3 702 75% 89%
*For the Low glucose range, 40-80 mg/dL (2.2-4.4 mmol/L), the value shown is the percent within 20
mg/dL (1.1 mmol/L).
The Clarke Error Grid was used to assess the clinical relevance of the differences between the Guardian RT
readings and the comparative blood glucose meter measurements. The Clarke Error Grid divides a
correlation plot into 5 zones. See the following table.
Results in zones A and B are considered clinically acceptable, while results in zones C, D, and E are
potentially dangerous and, therefore, clinically significant errors. The Clarke Error Grid zones are labeled
on the correlation plot.
Zone Description
A Clinically accurate, would lead to correct treatment decisions
B Would lead to benign decisions or no treatment
C Would lead to over-correction of normal glucose levels
D Would lead to failure to detect and treat high or low glucose levels
E Would lead to erroneous treatment decisions
Sensor accuracy 149
Appendix A