Table 3.

Sex- and age-specific reference intervals for myocardial enzyme activity in healthy population aged 1∼<18 years (n = 6322).

Analytes	Age group	Sex group	No. of samples	Lower limit	Upper limit	Confidence interval for lower limit	Confidence interval for upper limit
AST (U/L)	1∼<7	M + F	2219	22.7	51.9	22.3–23.0	50.6–52.9
	7∼<12	M	908	18.2	36.4	17.4–18.6	35.5–37.1
		F	898	16.0	33.8	15.3–16.3	33.6–34.9
	12∼<18	M	1119	15.4	33.3	15.0–15.8	32.3–33.8
		F	1178	13.7	26.6	13.2–14.1	26.3–27.3
LDH (U/L)	1∼<7	M + F	2219	434.9	737.7	431.2–438.6	732–743.4
	7∼<12	M	908	408.8	663.7	402.9–414.7	657.3–670.1
		F	898	373.8	642.1	367.9–379.8	635.0–649.1
	12∼<15	M	734	364.8	641.0	359.1–370.5	631.7–650.4
	15∼<18	M	385	314.6	568.6	305.9–323.3	558.6–578.7
	12∼<18	F	1178	315.7	554.9	311.6–319.6	548.6–561.2
CK (U/L)	1∼<18	M	3119	49.1	194.1	47.1–50.9	191.3–197.7
	1∼<7	F	1127	41.0	166.5	39.4–42.7	162.6–170.5
	7∼<12	F	898	39.3	155.4	37.5–41.2	151.6–159.2
	12∼<15	F	734	36.6	129.2	35.0–38.2	125.8–132.7
	15∼<18	F	444	32.0	105.9	30.4–33.6	102.3–109.6
CKMB (U/L)	1∼<7	M + F	2219	11.4	38.9	11.0–11.8	38.4–39.3
	7∼<15	M	1642	7.9	34.2	7.5–8.4	33.7–34.7
	7∼<12	F	898	7.4	30.7	6.8–8.0	30.2–31.3
	12∼<15	F	734	2.8	23.3	2.5–3.1	22.5–24.1
	15∼<18	F	444	2.7∗	15.5	2.7∗	14.5–16.9
	15∼<18	M	385	2.1	20.8	1.7–2.5	19.9–21.8

^∗2.7 U/L is the lowest detection limit. Actual values could be lower. M + F indicates that RI is shared by both genders.