Variation of Bone Turnover Markers in Childhood and Adolescence

Table 2

Biomedical reference ranges for BTMs in children.

		Age, years	2.5th percentile	97.5th percentile	90% CI for low limit	90% CI for high limit
P1NP (ng/mL)	Boys	0–6	266.5	2246.3	87.4–374.6	1864.1–2570.2
		6–12	221.4	1298.8	175.2–273.3	1175.0–1419.0
		>12	117.6	1532.1	106.8–350.4	1308.1–1537.0
	Girls	0–6	268.8	1935.0	182.1–354.9	1605.0–2473.6
		6–10	230.9	1809.0	30.5–286.5	1141.0–1987.0
		>10	97.2	1130.1	26.3–136.1	1034.8–1260.0
β-CTx (pg/mL)	Boys	0–6	560.3	2346.5	395.7–754.3	1994.2–2630.0
		6–12	796.0	2760.0	542.0–859.0	1940.0–3096.0
		>12	663.6	2996.0	663.3–898.2	2210.0–3010.0
	Girls	0–6	444.2	2678.3	245.1–613.2	1960.0–3096.0
		6–10	485.0	2618.0	180.5–637.8	2379.0–3140.0
		>10	211.2	2585.7	182.0–426.9	2270.0–3260.0
N-MID (ng/mL)	Boys	0–6	24.9	117.5	16.1–33.4	105.0–121.8
		6–12	31.6	138.7	28.9–36.9	118.6–177.9
		>12	19.0	143.6	18.6–36.7	120.7–144.7
	Girls	0–6	24.7	125.6	21.1–27.0	93.4–161.9
		6–10	27.8	114.6	9.9–37.7	106.9–144.6
		>10	17.4	129.1	6.8–22.3	114.5–144.2
ALP (U/L)	Boys	0–6	104	753	62–129	574–803
		6–12	140	402	106–147	368–443
		>12	93	599	92–125	554–599
	Girls	0–6	143	818	121–155	565–1952
		6–10	144	460	144–161	383–467
		>10	65	502	65–83	457–502
Ca (mmol/L)	Boys	0–6	2.26	2.66	2.24–2.28	0.261–2.72
		6–12	2.13	2.58	2.07–2.15	2.53–2.64
		>12	2.08	2.59	2.08–2.22	2.54–2.59
	Girls	0–6	2.30	2.70	2.18–2.33	2.66–2.72
		6–10	2.10	2.60	2.08–2.23	2.51–2.64
		>10	1.85	2.65	1.85–2.08	2.61–2.65
Pi (mmol/L)	Boys	0–6	1.26	2.44	1.21–1.34	2.18–2.30
		6–12	1.32	1.98	1.25–1.41	2.53–2.64
		>12	1.03	2.02	1.03–1.24	1.99–2.02
	Girls	0–6	1.39	2.28	1.17–1.44	2.20–2.36
		6–10	1.16	1.98	1.16–1.36	1.92–1.98
		>10	1.18	2.30	1.18–1.28	2.01–2.30
25(OH) vitamin D (ng/mL)	Boys	0–6	16.2	58.0	15.1–17.4	53.6–64.6
		6–12	11.7	47.6	8.6–12.7	42.2–66.4
		>12	8.8	39.8	8.8–11.0	33.9–39.9
	Girls	0–6	9.5	54.2	3.5–14.0	48.3–54.9
		6–10	9.5	43.6	6.6–12.2	38.7–53.4
		>10	11.6	52.0	10.8–13.0	47.2–57.6