Age- and Sex-Specific Reference Intervals for Myocardial Enzyme Activity in Healthy Chinese Han Population Aged 1∼<18 years

Table 1

Analytic parameters of myocardial enzyme activity on the VITROS 5600 Integrated System.

Enzyme	SI unit	Bias of accuracy (%)	Precision				Analytical measurement range (U/L)	Clinical reportable range (U/L)	Accreditation criteria
			Low level (%)		High level (%)
			Within-day	Between-day	Within-day	Between-day			Bias (%)	TE (%)
AST	U/L	4.86	1.40	1.42	1.40	1.52	9.0–653.0	9.0–6530.0	5.00	15.00
LDH	U/L	1.91	2.30	2.33	1.85	1.90	294.0–1473.0	294.0–14730.0	4.00	11.00
CK	U/L	4.85	2.15	4.20	1.79	3.27	21.5–1566.0	21.5–1566.0	5.50	15.50
CKMB	U/L	5.51	5.18	5.20	4.30	4.31	2.7–300.0	2.7–300.0	7.00	22.00

TE refers to total error; Bias and TE criteria are from Analytical quality specification for routine analytes in clinical biochemistry published by the Ministry of Health of the People’s Republic of China; due to lack of criteria for CKMB, bias and TE were recommended by our own clinical laboratory. Coefficient of variation (CV) for within-day precision should be < 1/4TE, and CV for between-day precision should be < 1/3TE according to Guidance on the Application of Accreditation Criteria for the Medical Laboratory Quality and Competence in the Field of Clinical Chemistry published by the China National Accreditation Service for Conformity Assessment.