Sensor Glucose Readings - Dexcom G5 mobile Quick Start Manual

8.2 Sensor Glucose Readings

Device
BG Meter
Smart Device
Receiver
44 • Dexcom G5 Mobile CGM System Quick Start Guide
What you see
(Continued on next page)
Problem
Sensor readings
and BG meter
glucose values
often don't show
the same
What you do
Differences are not
uncommon.
Readings from different
body fluids may be
slightly different:
Meter - from blood
Sensor - from
interstitial fluid
20/20 Rule
If the meter shows 80
or less, CGM should
read within ± 20 points.
If the meter shows
80 or above, the CGM
should read ± 20%.
Example: a 202 mg/dL
sensor reading and a
188 mg/dL glucose
meter value = a 7%
difference (this is still
considered accurate).
In this example, the
Dexcom could show
up to 225 and still be
considered accurate
Outside of 20/20 rule:
Calibrate again.