eversense XL - Clarke Error Grid Analysis

135
Eversense XL CGM User Guide
18
Clarke Error Grid Analysis
The Clarke Error Grid Analysis (EGA) is one of the standards for quantifying the accuracy of CGM systems.
Clarke EGA measures accuracy by comparing subject glucose values taken from their CGM system to reference
values taken in a lab.
Clarke EGA calculates accuracy by looking at the number and percentage of data points that fell into 5 “clinical risk”
zones. Data is presented in both graph and chart formats.
• Zone A (no risk) contains CGM values that fell within ±20% of the reference values.
– Zone A values are considered to be within the acceptable accuracy range of CGM systems.
• Zone B (no risk) contains CGM values that fell outside ±20% of the reference values.
– Zone B values are not considered to be within the acceptable accuracy range, but their dierence from
the reference values would not lead a subject to making an inappropriate treatment decision.
• Zone C (low risk) contains CGM values that diered enough from the reference values that a subject might make
an unnecessary treatment decision based on the CGM information.
• Zone D (medium risk) contains CGM values that were correctly identified as hypoglycaemic or hyperglycaemic
bythe reference system but not the CGMsystem.
– Not correctly identifying a CGM value as hypoglycaemic or hyperglycaemic is a potentially dangerous
situation.
• Zone E (high risk) contains CGM values that were incorrectly identified as hypoglycaemic when the reference
system correctly identified them as hyperglycaemic (and vice versa).
– Mistakenly identifying a CGM value as hypoglycaemic when it is actually hyperglycaemic (or vice versa)
is a potentially dangerous situation.