Table 2.

Glucose meters' QC performance at different Sigma values.

		Number of meter	Sigma value ∼<3	Sigma value ∼<3.5	Sigma value ∼<4	Sigma value ≥ 4
QC low level, meter SD/all-meter SD	∼ ≤ 1	327	0	0	0	327
	∼ ≤ 1.5	248	0	4	34	210
	>1.5	19	4	12	3	0
QC low level, meter Bias/all-meter SD	∼ ≤ 1	589	4	16	35	534
	∼ ≤ 1.5	5	0	0	2	3
	>1.5	0	0	0	0	0
QC high level, meter SD/all-meter SD	∼ ≤ 1	350	0	0	0	350
	∼ ≤ 1.5	247	2	22	78	145
	>1.5	13	10	3	0	0
QC high level, meter Bias/all-meter SD	∼ ≤ 1	599	7	25	80	487
	∼ ≤ 1.5	11	3	1	0	7
	>1.5	0	0	0	0	0

All-meter SD of the six months at the low QC level was 0.15 mmo/L, at the high QC level 0.47 mmol/L. QC; quality control. SD; Standard deviation.