Table 2.

Comparison of Point and Trend Accuracy Parameters for Different Commercially Available CGM Devices

Point accuracy – Euglycemia, 70 < BG < 180 mg/dl (3.9–10.0 mmol/liter)a
		Guardian®b	DexCom STS®b	DexCom SEVEN PLUS®c	Navigator®b	GlucoDay®Sb	GlucoMen®Day
Mean absolute error	mg/dl	16.4	22.3	n.a.d	16.0	15.7	11.9
	mmol/liter	0.91	1.24	n.a.	0.89	0.87	0.66
Mean absolute relative error (%)		15.2	21.2	15.0	15.3	15.6	10.4
Median absolute error	mg/dl	14.8	19.1	n.a.	15.3	10.8	10.1
	mmol/liter	0.82	1.06	n.a.	0.85	0.60	0.56
Median absolute relative error (%)		13.3	18.4	13.0	11.8	10.7	7.7
% readings within ISO 15197 requirementse		73.2	52.2	74.0	72.2	76.9	89.3
Point Accuracy – Hypoglycemia, BG ≥ 70 mg/dl [3.9 mmol/liter]f
Mean absolute error	mg/dl	9.9	13.1	n.a.	6.5	8.5	7.4
	mmol/liter	0.55	0.73	n.a.	0.36	0.47	0.41
Mean absolute relative error (%)		16.1	21.5	25.0	10.3	17.5	14.2
Median absolute rrror	mg/dl	7.6	11.52	n.a.	4.3	7.2	5.9
	mmol/liter	0.42	0.64	n.a.	0.24	0.40	0.33
Median absolute relative error (%)		13.8	22.5	20.0	7.4	15.6	9.6
% readings within ISO 15197 requirementse		76.5	52.9	n.a.	79.4	83.0	80.0
Rate accuracy – Descent into hypoglycemia
Absolute rate deviation	mg/dl/min	0.87	0.72	n.a.	0.66	1.74	0.75
	mmol/liter/h	2.9	2.4	n.a.	2.2	5.8	2.5
Rate accuracy – Ascent from hypoglycemia
Absolute rate deviation	mg/dl/min	0.90	0.99	n.a.	0.99	2.79	0.45
	mmol/liter/h	3.0	3.3	n.a.	3.3	9.3	1.5

^aDexCom SEVEN PLUS system assumes the euglycemic range to be 80–180 mg/dl (4.4–10.0 mmol/liter).³⁰

^bData from Kovatchev BP, Anderson S, Heinemann L, Clarke WL. Comparison of the numerical and clinical accuracy of four continuous glucose monitors. Diabetes Care. 2008;31:1160–4.²⁰

^cData from: SEVEN PLUS User Guide. Dexcom, Inc: San Diego, CA.³⁰

^dn.a., data not available

^eOverall percentage of readings falling within ±15 mg/dl (if <75 mg/dl) and ±20% (if ≥75 mg/dl) of the reference values, according to the ISO 15197 accuracy requirements (bias plot).²³ ISO, International Organization for Standardization.

^fDexCom SEVEN plus system defines as hypoglycemia BG levels ≥80 mg/dl (≥4.4 mmo/liter).³⁰