Reference values of thirty-one frequently used laboratory markers for 75-year-old males and females

Figures & data

Table I. Total analytical imprecision at two levels for the Vitros methods used to calculate the reference intervals.

Analyte	Concentration (two levels)	Coefficient of variation (CV)
Alanine aminotransferase (ALT)	0.66 µkat/L	4.9%
	3.15 µkat/L	1.3%
Albumin	23 g/L	2.4%
	47 g/L	1.8%
Alkaline phosphatase	1.6 µkat/L	2.8%
	8.5 µkat/L	3.1%
Apolipoprotein A1	1.08 g/L	2.1%
	1.91 g/L	3.7%
Apolipoprotein B	0.89 g/L	2.1%
	1.84 g/L	1.7%
Bilirubin	26 µmol/L	2.9%
	256 µmol/L	1.1%
Calcium	2.1 mmol/L	1.7%
	3.0 mmol/L	1.5%
Chloride	81 mmol/L	0.9%
	105 mmol/L	0.8%
Cholesterol	3.8 mmol/L	1.0%
	6.3 mmol/L	1.0%
HDL-cholesterol	1.0 mmol/L	2.5%
	1.6 mmol/L	2.2%
Creatinine	76 µmol/L	1.3%
	504 µmol/L	1.2%
Creatine kinase	2.7 µkat/L	3.3%
	15.2 µkat/L	4.1%
C-reactive protein (CRP)	5.5 mg/L	5.0%
	84 mg/L	5.9%
γ-Glutamyltransferase (GGT)	1.2 µkat/L	2.6%
	7.4 µkat/L	1.8%
Glucose	4.2 mmol/L	2.5%
	6.5 mmol/L	2.4%
Iron	19 µmol/L	2.2%
	45 µmol/L	1.5%
Lactate dehydrogenase (LDH)	2.7 µkat/L	2.5%
	9.2 µkat/L	1.5%
Lipase	2.7 µkat/L	2.6%
	10.0 µkat/L	1.0%
Magnesium	0.9 mmol/L	1.7%
	1.8 mmol/L	1.2%
Phosphate	1.1 mmol/L	1.4%
	2.3 mmol/L	0.7%
Potassium	3.1 mmol/L	0.9%
	5.4 mmol/L	0.7%
Sodium	117 mmol/L	1.5%
	143 mmol/L	1.7%
Transferrin	1.3 g/L	2.0%
	6.0 g/L	3.7%
Triglycerides	1.3 mmol/L	0.7%
	2.7 mmol/L	1.1%
Urate	250 µmol/L	1.2%
	630 µmol/L	1.4%
Urea	5.6 mmol/L	2.5%
	20.3 mmol/L	2.2%

Table II. Traceability of standardizations of methods used to calculate the reference intervals.

Alanine aminotransferase (ALT)	IFCC reference method
Albumin	NIST SRM 927c
Alkaline phosphatase	IFCC reference method
Apolipoprotein A1	WHO-IFCC RR SP1-01
Apolipoprotein B	WHO-IFCC RR SP3-08
Bilirubin	NIST SRM 916a
Calcium	NIST SRM 915a
Chloride	NIST SRM 919a
Cholesterol	NIST 911b
Creatinine	NIST, SRM914
Creatine kinase	Scandinavian Committee on Enzymes
C-reactive protein (CRP)	IRMM/IFCC CRM 470
Glucose	Isotope dilution mass spectrometry (IDMS)
γ-Glutamyltransferase (GGT)	IFCC reference method
HDL-cholesterol	NIST SRM 911b
Iron	NIST SRM 937
Lactate dehydrogenase (LDH)	Pyruvate-to-lactate total lactate dehydrogenase method
Magnesium	NIST SRM 929
Phosphate	NIST SRM 200
Potassium	NIST SRM 918a
Sodium	NIST SRM 919a
Transferrin	IRMM/IFCC CRM 470
Triglycerides	CDC reference method
Urate	NIST SRM 913a
Urea	NIST SRM 912a

Table III. Basic characteristics for the persons included in the reference material (n = 727).

	Females, median (IQR)	Males, median (IQR)
Females/males (number)	373	354
Height (cm)	161 (157–165)	175 (172–180)
Weight (kg)	69 (60–78)	79 (73–88)
Waist circumference (cm)	91 (82–98)	93 (86–102)
BMI (kg/m^2)	26.3 (23.4–29.4)	26.1 (24.0–28.5)
Waist/hip ratio	0.91 (0.87–0.97)	0.97 (0.92–1.01)
DBP (mmHg)	76 (70–80)	76 (70–84)
SBP (mmHg)	150 (140–164)	146 (134–158)

BMI = body mass index; DBP = diastolic blood pressure; SBP = systolic blood pressure.

Table IV. Calculated upper (97.5 percentile) and lower (2.5 percentile) limits for the reference intervals and 90% confidence intervals (in brackets).

ALT (µkat/L)
Males, all	0.21 (0.18–0.23)	–	0.75 (0.64–0.85)
Males, without CVD	0.20 (0.18–0.23)	–	0.76 (0.62–0.90)
Females, all	0.20 (0.18–0.20)	–	0.60 (0.51–0.69)
Females, without CVD	0.19 (0.18–0.20)	–	0.60 (0.52–0.67)
Albumin (g/L)
Males, all	37.2 (36.3–38.1)	–	52.5 (51.7–53.2)
Males, without CVD	37.5 (36.7–38.2)	–	52.1 (51.1–53.2)
Females, all	38.2 (37.7–38.8)	–	51.1 (50.3–52.0)
Females, without CVD	38.2 (37.7–38.8)	–	51.1 (50.3–52.3)
Alkaline phosphatase (µkat/L)
Males, all	0.86 (0.81–0.91)	–	2.19 (1.99–2.39)
Males, without CVD	0.86 (0.80–0.92)	–	2.09 (1.84–2.33)
Females, all	0.84 (0.78–0.90)	–	2.34 (2.04–2.65)
Females, without CVD	0.86 (0.81–0.91)	–	2.42 (2.11–2.74)
Apolipoprotein A1 (g/L)
Males, all	1.10 (1.07–1.12)	–	2.22 (2.13–2.31)
Males, without CVD	1.11 (1.08–1.14)	–	2.26 (2.10–2.42)
Females, all	1.33 (1.28–1.38)	–	2.50 (2.30–2.71)
Females, without CVD	1.34 (1.29–1.40)	–	2.52 (2.32–2.72)
Apolipoprotein B (g/L)
Males, all	0.64 (0.59–0.68)	–	1.61 (1.55–1.67)
Males, without CVD	0.66 (0.61–0.71)	–	1.60 (1.54–1.66)
Females, all	0.74 (0.70–0.77)	–	1.71 (1.66–1.76)
Females, without CVD	0.73 (0.69–0.77)	–	1.70 (1.65–1.76)
Apolipoprotein B/Apolipoprotein A1 ratio
Males, all	0.4 (0.3–0.4)	–	1.2 (1.1–1.2)
Males, without CVD	0.4 (0.3–0.4)	–	1.1 (1.0–1.2)
Females, all	0.3 (0.3–0.4)	–	1.1 (1.0–1.1)
Females, without CVD	0.3 (0.3–0.4)	–	1.1 (1.0–1.1)
Bilirubin (µmol/L)
Males, all	1.7 (1.6–1.9)	–	18.8 (16.8–20.8)
Males, without CVD	1.8 (1.6–2.0)	–	18.2 (16.3–20.1)
Females, all	1.7 (1.7–1.7)	–	11.8 (11.1–12.6)
Females, without CVD	1.7 (1.7–1.7)	–	11.6 (10.9–12.3)
Calcium (mmol/L)
Males, all	2.18 (2.16–2.20)	–	2.55 (2.52–2.59)
Males, without CVD	2.19 (2.18–2.20)	–	2.55 (2.52–2.58)
Females, all	2.22 (2.19–2.24)	–	2.57 (2.54–2.60)
Females, without CVD	2.22 (2.20–2.24)	–	2.57 (2.54–2.60)
Chloride (mmol/L)
Males, all	102 (101–102)	–	111 (110–112)
Males, without CVD	102 (101–103)	–	111 (110–111)
Females, all	99 (98–101)	–	111 (111–112)
Females, without CVD	99 (98–101)	–	111 (111–112)
Cholesterol (mmol/L)
Males, all	3.2 (3.0–3.4)	–	7.4 (7.2–7.6)
Males, without CVD	3.5 (3.3–3.8)	–	7.4 (7.2–7.6)
Females, all	3.9 (3.6–4.2)	–	7.9 (7.7–8.2)
Females, without CVD	4.1 (3.8–4.4)	–	8.0 (7.7–8.3)
Creatinine (µmol/L)
Males, all	62 (61–64)	–	133 (123–143)
Males, without CVD	62 (60–64)	–	123 (111–136)
Females, all	53 (51–54)	–	101 (96–107)
Females, without CVD	53 (51–54)	–	98 (93–104)
Creatine kinase (µkat/L)
Males, all	0.45 (0.35–0.54)	–	4.90 (4.06–5.77)
Males, without CVD	0.44 (0.32–0.56)	–	5.19 (4.12–6.25)
Females, all	0.44 (0.36–0.52)	–	3.35 (2.91–3.80)
Females, without CVD	0.46 (0.37–0.55)	–	3.45 (2.96–3.94)
C-reactive protein (CRP) (mg/L)
Males, all	0.32 (0.23–0.42)	–	24.11 (16.02–32.20)
Males, without CVD	0.36 (0.25–0.47)	–	23.50 (17.11–29.89)
Females, all	0.37 (0.29–0.45)	–	15.89 (12.46–19.32)
Females, without CVD	0.37 (0.29–0.44)	–	16.49 (11.89–21.10)
γ-Glutamyltransferase (GGT) (µkat/L)
Males, all	0.29 (0.28–0.31)	–	2.12 (1.87–2.38)
Males, without CVD	0.29 (0.27–0.32)	–	2.06 (1.79–2.33)
Females, all	0.25 (0.24–0.26)	–	1.77 (1.34–2.20)
Females, without CVD	0.25 (0.24–0.26)	–	1.62 (1.14–2.09)
Glucose (mmol/L)
Males, all	3.8 (3.7–3.9)	–	6.6 (6.2–7.0)
Males, without CVD	3.8 (3.7–4.0)	–	6.5 (6.1–6.8)
Females, all	3.8 (3.6–4.0)	–	6.2 (6.0–6.3)
Females, without CVD	3.7 (3.6–4.0)	–	6.2 (6.0–6.4)
HDL-cholesterol (mmol/L)
Males, all	0.77 (0.72–0.82)	–	2.29 (2.10–2.48)
Males, without CVD	0.80 (0.75–0.84)	–	2.35 (2.13–2.58)
Females, all	1.02 (0.98–1.06)	–	2.78 (2.57–3.00)
Females, without CVD	1.03 (0.98–1.09)	–	2.82 (2.60–3.04)
Iron (µmol/L)
Males, all	8.3 (6.8–9.9)	–	34.3 (32.9–35.6)
Males, without CVD	8.4 (6.3–10.4)	–	34.8 (33.3–36.3)
Females, all	8.8 (8.0–9.7)	–	28.8 (27.5–30.1)
Females, without CVD	8.9 (7.9–9.8)	–	28.7 (27.5–30.0)
Lactate dehydrogenase (LDH) (µkat/L)
Males, all	1.6 (1.5–1.7)	–	3.3 (3.0–3.6)
Males, without CVD	1.6 (1.5–1.7)	–	3.4 (3.0–3.8)
Females, all	1.6 (1.5–1.7)	–	3.4 (3.3–3.5)
Females, without CVD	1.6 (1.5–1.7)	–	3.3 (3.2–3.4)
LDL-cholesterol (mmol/L)
Males, all	1.4 (1.2–1.7)	–	5.4 (5.1–5.7)
Males, without CVD	1.8 (1.6–1.9)	–	5.4 (5.0–5.7)
Females, all	1.8 (1.6–2.0)	–	5.4 (5.2–5.6)
Females, without CVD	1.8 (1.6–2.0)	–	5.4 (5.1–5.7)
LDL-cholesterol/HDL-cholesterol ratio
Males, all	0.9 (0.8–1.1)	–	4.6 (4.3–5.0)
Males, without CVD	1.1 (0.9–1.2)	–	4.6 (4.4–4.9)
Females, all	0.9 (0.8–1.0)	–	4.2 (3.9–4.5)
Females, without CVD	0.9 (0.8–1.0)	–	4.1 (3.8–4.5)
Lipase (µkat/L)
Males, all	0.60 (0.52–0.68)	–	5.61 (4.88–6.34)
Males, without CVD	0.60 (0.48–0.73)	–	5.35 (4.68–6.03)
Females, all	0.74 (0.61–0.87)	–	5.84 (4.99–6.68)
Females, without CVD	0.70 (0.55–0.85)	–	5.66 (4.79–6.53)
Magnesium (mmol/L)
Males, all	0.72 (0.70–0.74)	–	0.94 (0.92–0.95)
Males, without CVD	0.71 (0.69–0.74)	–	0.94 (0.93–0.96)
Females, all	0.70 (0.68–0.72)	–	0.93 (0.92–0.94)
Females, without CVD	0.70 (0.67–0.73)	–	0.93 (0.92–0.94)
Phosphate (mmol/L)
Males, all	0.86 (0.82–0.90)	–	1.38 (1.33–1.42)
Males, without CVD	0.84 (0.77–0.90)	–	1.35 (1.32–1.38)
Females, all	0.98 (0.93–1.02)	–	1.47 (1.44–1.50)
Females, without CVD	0.97 (0.92–1.01)	–	1.47 (1.43–1.51)
Potassium (mmol/L)
Males, all	3.7 (3.6–3.8)	–	4.9 (4.7–5.0)
Males, without CVD	3.7 (3.6–3.8)	–	4.9 (4.7–5.0)
Females, all	3.7 (3.6–3.8)	–	4.8 (4.7–4.8)
Females, without CVD	3.6 (3.5–3.7)	–	4.8 (4.7–4.8)
Sodium (mmol/L)
Males, all	137 (137–138)	–	146 (145–147)
Males, without CVD	137 (136–138)	–	145 (145–146)
Females, all	135 (134–137)	–	145 (145–146)
Females, without CVD	135 (134–137)	–	145 (145–146)
TIBC (µmol/L)
Males, all	44.4 (41.6–47.2)	–	82.2 (76.8–87.6)
Males, without CVD	43.8 (41.0–46.7)	–	76.8 (71.6–82.0)
Females, all	45.3 (42.8–47.5)	–	82.3 (78.7–85.9)
Females, without CVD	45.0 (42.4–47.5)	–	79.3 (76.6–82.0)
Transferrin (g/L)
Males, all	1.79 (1.70–1.88)	–	3.27 (3.06–3.48)
Males, without CVD	1.77 (1.67–1.87)	–	3.06 (2.85–3.27)
Females, all	1.80 (1.70–1.89)	–	3.27 (3.13–3.42)
Females, without CVD	1.79 (1.68–1.89)	–	3.16 (3.06–3.25)
Transferrin saturation (%)
Males, all	13 (10–16)	–	57 (54–60)
Males, without CVD	13 (9–18)	–	59 (55–63)
Females, all	13 (12–14)	–	50 (45–55)
Females, without CVD	14 (12–16)	–	51 (46–56)
Triglycerides (mmol/L)
Males, all	0.64 (0.58–0.69)	–	3.14 (2.63–3.66)
Males, without CVD	0.63 (0.58–0.69)	–	2.92 (2.54–3.30)
Females, all	0.60 (0.51–0.69)	–	3.06 (2.48–3.63)
Females, without CVD	0.59 (0.50–0.67)	–	3.18 (2.57–3.78)
Urate (µmol/L)
Males, all	221 (201–242)	–	495 (474–515)
Males, without CVD	217 (196–238)	–	484 (455–512)
Females, all	178 (170–187)	–	434 (401–467)
Females, without CVD	178 (168–188)	–	422 (397–446)
Urea (mmol/L)
Males, all	4.00 (3.73–4.27)	–	11.22 (9.75–12.69)
Males, without CVD	3.92 (3.58–4.26)	–	10.51 (9.08–11.94)
Females, all	3.63 (3.51–3.75)	–	9.60 (9.14–10.07)
Females, without CVD	3.62 (3.50–3.74)	–	9.48 (8.74–10.21)