Dexcom G4 Professional User Manual page 185

14
Participants used the System for seven days. Thirty-six participants
each wore 2 sensors. Sensors were calibrated approximately once
every 12 hours, using the self-monitoring blood glucose (SMBG)
meter values obtained from the LifeScan OneTouch Ultra 2 meter.
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Throughout the 7-day wear period, the sensor was calibrated with an
average of 2 fingersticks per day (approximately once every 12 hours).
All subjects were evaluated in a controlled clinic environment on Day
1, Day 4, and Day 7 of the 7-day wear period. While using the System
in the clinic, participants had their blood glucose measured every 15
minutes with a reliable laboratory method, the Yellow Springs Instrument
2300 STAT Plus™ Glucose Analyzer. This instrument is referred to as
the "YSI." Readings from the System were reported every 5 minutes
and paired with YSI values in order to characterize how well the System
readings agreed with laboratory standard blood glucose results. The
remainder of the study took place at home, the System performance
was also paired with the comparative LifeScan OneTouch Ultra 2 meter
results, and that is referred to as the 'SMBG'.
Agreement
Agreement between the System and blood glucose values is
characterized using paired System and YSI values. The System and
YSI results were compared by pairing the YSI blood glucose value to
a System glucose reading that occurred immediately after the YSI was
collected.
The agreement of the System to blood glucose value was assessed by
calculating the percentage of System readings that were within 15%,
20%, 30%, 40% and greater than 40% of the YSI values. For readings
less than or equal to 80 mg/dL (4.4 mmol/L) the absolute difference
in mg/dL (mmol/L) between the two glucose results was calculated.
For values greater than 80 mg/dL (4.4 mmol/L) the absolute percent
difference (%) from the YSI values was calculated. The percentages
of total readings within 15 mg/dL (0.8 mmol/L) or 15%, 20 mg/dL (1.1
mmol/L) or 20%, 30 mg/dL (1.7 mmol/L) or 30%, 40 mg/dL (2.2 mmol/L)
or 40% or greater than 40 mg/dL (2.2 mmol/L) or 40% were then
calculated in Table 1-A and Table 1-B.
184 | Dexcom G4 PLATINUM Professional Continuous Glucose Monitoring System