. 2018 Jun 15;28(2):020708. doi: 10.11613/BM.2018.020708

Table 3. Sigma metrics for the proficiency testing (PT)-based approach.

Item	Sample number	Mean			CV (%)			Bias (%)			σ_CLIA			σ_WS/T
Item	Sample number	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension
Alb	201721	46	49	51	1.0	1.4	0.8	- 1.2	- 1.0	5.8	8.4	6.6	5.2	4.6	3.7	0.3^†
	201722	24	26	26	1.2	3.0	0.8	- 2.2	0.5	2.6	6.4	3.2	9.5	3.1	1.9^†	4.4
	201723	32	35	35	1.0	2.1	1.3	- 1.8	- 0.4	3.6	8.5	4.5	4.8	4.4	2.6^†	1.8^†
	201724	46	49	52	2.3	1.6	1.1	- 1.1	- 1.5	7.2	3.8	5.5	2.6^†	2.1^†	2.9^†	- 1.1^†
	201725	37	40	41	1.3	2.1	0.8	- 2.9	- 2.2	2.9	5.5	3.8	9.4	2.4^†	1.9^†	4.1
ALT	201721	160	153	164	0.6	1.0	0.9	- 2.8	- 2.3	- 1.3	27.7	18.3	21.5	21.3	14.2	16.9
	201722	31	29	32	3.0	4.0	4.6	- 2.8	- 1.1	0.7	5.8	4.7	4.2	4.5	3.7	3.3
	201723	77	74	81	0.8	2.7	2.4	- 3.4	- 3.3	0.1	19.8	6.2	8.2	15	4.7	6.6
	201724	144	137	149	0.8	1.3	2.0	- 2.5	- 2.6	0.5	21.1	13.1	9.6	16.2	10.1	7.7
	201725	100	97	105	1.2	1.7	1.8	- 4.7	- 3.4	- 2.6	13	10	9.7	9.6	7.6	7.5
BT	201721	128.1	121.1	129.4	1.1	0.8	0.7	- 6.3	- 4.0	- 6.8	13	19.6	18.6	8.3	13.5	11.5
	201722	12.5	11.3	13.8	1.3	1.8	2.2	- 7.1	- 8.5	1.7	36.8*	27.6*	22.0*	6.3	3.6	6.1
	201723	25.4	23.5	27.8	0.9	1.4	1.3	- 14.6	- 7.4	0.1	11.3	15	18.9	0.4^†	5.5	11.7
	201724	85.9	82.0	89.1	1.0	1.9	0.6	- 4.2	- 4.9	- 5.9	16	7.8	22.7	11	5.2	14.7
	201725	38.16	35.9	41.0	1.3	1.2	1.3	- 12.9	- 7.8	- 4.0	5.6	10.4	12.3	1.7^†	6.2	8.4
Item	Sample number	Mean			CV (%)			Bias (%)			σ_CLIA			σ_WS/T
Item	Sample number	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension	Beckman AU5800	Roche C8000	Siemens Dimension
Glc	201721	13.4	13.3	14.2	1.2	1.4	1.6	- 2.7	- 2.1	3.5	6.1	5.6	4.1	3.6	3.5	2.2^†
	201722	3.8	3.7	4.0	1.1	1.1	2.2	- 3.0	- 2.9	5.5	6.6	6.7	2^†	3.8	3.9	0.7^†
	201723	6.6	6.6	7.1	1.4	1.1	2.4	- 3.1	- 2.8	4.5	5	6.9	2.3^†	2.8^†	4	1.1^†
	201724	10.8	10.8	11.5	1.3	1.2	1.8	- 2.8	- 2.6	4.3	5.4	6.2	3.2	3.2	3.7	1.5^†
	201725	7.3	7.2	7.8	1.4	0.9	1.4	- 4.5	- 4.5	2.4	3.8	6.5	5.3	1.7^†	3	3.2
CREA	201721	466	464	452	0.8	1.2	0.7	- 0.2	2.1	0.4	19.4	11	21	15.5	8.4	16.7
	201722	85	88	82	0.8	1.2	2.1	9.6	5.4	0.8	28.8*	20.2*	14.9*	3.1	5.3	5.3
	201723	223	225	218	0.6	1.2	2.9	2.9	1.8	1.5	19.3	11.3	4.7	14.5	8.7	3.7
	201724	469	467	455	0.8	1.1	1.2	- 0.7	1.4	- 0.7	17.4	12.2	11.9	13.7	9.5	9.4
	201725	289	289	284	0.7	1.0	1.0	- 0.2	- 0.2	- 0.1	21.2	14.8	14.9	16.9	11.8	11.9
Urea	201721	17.41	17.58	18.17	2.0	3.6	1.3	- 3.9	- 2.6	0.2	2.6^†	1.8^†	7.1	2.1^†	1.5^†	6.3
	201722	4.05	4.21	4.25	2.0	3.1	3.0	- 7.0	- 1.8	- 1.0	8.8*	7.1*	7.7*	0.5^†	2^†	2.4^†
	201723	9.31	9.49	9.77	2.2	3.0	1.4	- 5.1	- 2.4	- 0.4	2.5*^†	2.6*^†	6.9*	1.3^†	1.8^†	5.5
	201724	15.39	15.62	16.12	1.7	3.6	1.8	- 4.0	- 2.5	- 0.6	3	1.8^†	4.8	2.4^†	1.5^†	4.3
	201725	11.11	11.28	11.76	2.4	3.3	1.9	- 6.1	- 4.2	- 0.9	1.2^†	1.5^†	4.2	0.8^†	1.2^†	3.7
K	201721	6.3	6.4	6.3	1.2	0.6	0.8	0.6	0.6	0.4	6.4*	12.8*	9.2*	4.7	9.6	6.9
	201722	2.7	2.8	2.7	1.0	1.2	0.9	- 2.3	- 0.5	- 2.3	16.6*	14.7*	17.3*	3.8	4.7	4
	201723	4.3	4.4	4.3	0.5	0.6	0.8	0.4	0.1	0.5	21.8*	20.0*	14.4*	10.9	10.5	7.2
	201724	6.0	6.0	6.0	0.5	0.5	0.9	1.0	0.7	0.6	14.5*	17.0*	8.6*	9.8	12	5.9
	201725	4.7	4.8	4.7	0.7	0.3	1.1	- 1.0	- 1.1	- 1.2	14.1*	31.1*	8.7*	7.3	16.4	4.4
Na	201721	157	159	155	0.8	0.6	0.7	0.1	0.4	- 1.4	3.2*	3.6*	1.8*^†	5.1	6.1	3.9
	201722	108	111	112	0.8	0.9	0.8	- 2.5	0.3	1.0	1.4*^†	3.6*	3.3*	1.8^†	4	3.9
	201723	128	130	129	0.4	0.8	0.8	- 0.8	0.5	0.3	5.2*	3.4*	3.5*	7.1	4.5	4.6
	201724	153	154	153	0.5	0.5	1.1	0.3	2.2	0.5	5.0*	0.9*^†	2.0*^†	8.1	3.8	3.3
	201725	133	135	135	0.5	0.5	1.2	- 2.1	- 0.7	- 1.0	1.5^†	5.1	1.7^†	3.5	7.4	2.7^†
Cl	201721	108	107	105	0.8	0.7	0.9	0.7	1.7	- 2.6	5.3	5	2.7^†	4.1	3.5	1.6^†
	201722	76	72	72	0.6	0.8	1.2	0.9	3.9	- 1.4	7.2	1.4^†	3	5.5	0.1^†	2.1^†
	201723	89	86	85	0.4	0.6	0.9	0.7	2.9	- 2.0	10	3.7	3.3	7.7	2^†	2.2^†
	201724	108	106	105	0.6	0.5	0.6	0.8	2.1	- 0.9	6.9	5.6	6.6	5.3	3.7	5
	201725	96	94	93	0.5	0.4	0.7	- 1.1	1.4	- 2.8	7.7	9.7	3	5.7	7	1.6
Ca	201721	3.14	3.21	3.03	1.2	1.0	1.9	1.2	3.5	- 1.0	5.6*	4.4*	3.8*	3.1	1.5^†	2.1^†
	201722	1.84	1.92	1.80	1.2	0.8	1.7	1.2	4.4	- 1.3	10.5*	10.9*	7.4*	3.3	0.8^†	2.2^†
	201723	2.73	2.82	2.67	0.8	0.8	1.3	1.1	3.8	- 1.5	10.4*	6.5*	5.9*	5	1.5^†	2.7^†
	201724	3.02	3.12	2.92	0.8	0.7	1.2	0.8	4.0	- 2.0	9.1*	6.0*	5.3*	5.1	1.4^†	2.5^†
	201725	2.72	2.81	2.65	0.6	0.7	0.9	0.0	2.1	- 3.4	14.7*	9.9*	6.5*	8.8	4.2	1.7^†
*TEa calculated by using absolute bias to calculate σ; not marked indicates using percentage bias to calculate σ. ^† Sigma values < 3. TEa_CLIA - allowable total error derived from US Clinical Laboratory Improvement Amendments 1988 (CLIA ‘88). TEa_WS/T - allowable total error derived from the People’s Republic of China Health Industry Standard (WS/T403-2012). Alb - albumin, g/L. ALT - alanine aminotransferase, U/L 37 °C. BT - bilirubin, total, µmol/L. Glc - glucose, mmol/L. CREA - creatinine, µmol/L. Urea, mmol/L. K - potassium, mmol/L. Na - sodium, mmol/L. Cl - chlorides, mmol/L. Ca - calcium, mmol/L.