Examining within-session test-retest reliability of four bioimpedance devices among adults across a wide age range

Kworweinski Lafontant; David H. Fukuda; Sofea Smith; Jack Livingston; Michelle Da Silva Barbera; Ngoc Linh Nhi Nguyen; Edwin Rodriguez-Cruz; Susan Kampiyil; Katie R. Hirsch; Sarah K. Fretti; Jeffrey R. Stout

doi:10.2478/joeb-2026-0010

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Examining within-session test-retest reliability of four bioimpedance devices among adults across a wide age range

Journal of Electrical Bioimpedance

Volume 17 (2026): Issue 1 (January 2026)

By: Kworweinski Lafontant, David H. Fukuda, Sofea Smith, Jack Livingston, Michelle Da Silva Barbera, Ngoc Linh Nhi Nguyen, Edwin Rodriguez-Cruz, Susan Kampiyil, Katie R. Hirsch, Sarah K. Fretti and Jeffrey R. Stout

Open Access

|Aug 2026

Figures & Tables

Placement of dual-tab electrodes on right hand and foot. Participants were positioned supine on a padded table with a pillow underneath their head and their arms and legs abducted.

Table 1.

Participant demographics (N = 96).

Age (years)	46.1 ± 21.7
(19 – 81)
Weight (kg)	73.7 ± 14.9
(46.5 – 111.2)
Height (cm)	167.0 ± 9.4
(123.0 – 190.0)
BMI (kg/m²)	26.4 ± 5.2
(17.1 – 47.1)
Sex	M: 35 (36.5%)
F: 61 (63.5%)
Ethnicity	H: 16 (16.7%)
NH: 80 (83.3%)
Race	A: 7 (7.3%)
	B: 6 (6.3%)
	L: 6 (6.3%)
M: 3 (3.1%)
W: 70 (72.8%)
O: 4 (4.2%)

[i] Note. BMI = body mass index, M = male, F = female, H = Hispanic, NH = non-Hispanic, A = Asian, B = Black, L = Latino, M = Middle Eastern/North African, W = White, O = other. Data are presented as mean ± standard deviation, n (%), or range.

Table 2.

Whole-body bioimpedance by device at various frequencies.

*InBody 970*	Z (Ω)	Xc (Ω)	R (Ω)	PhA (°)
5kHz	675.8 ± 95.4	29.0 ± 6.1	675.2 ± 95.4	2.48 ± 0.53
(496.6 – 915.7)	(16.1 – 46.7)	(496.2 – 914.9)	(1.52 – 3.94)
50kHz	600.1 ± 90.6	58.0 ± 10.3	597.1 ± 90.6	5.60 ± 0.97
(415.9 – 821.5)	(34.9 – 83.1)	(411.9 – 818.0)	(3.74 – 7.84)
250kHz	541.8 ± 84.9	44.8 ± 6.7	539.9 ± 84.7	4.78 ± 0.54
(361.6 – 747.4)	(29.7 – 60.3)	(359.6 – 745.6)	(3.81 – 6.00)
500kHz	524.4 ± 82.6	-	-	-
(348.0 – 727.6)
1000kHz	509.6 ± 80.5	-	-	-
(337.3 – 709.6)
*InBody 770*	Z (Ω)	Xc (Ω)	R (Ω)	PhA (°)
5kHz	681.1 ± 97.0	30.8 ± 6.5	680.3 ± 97.0	2.61 ± 0.53
(495.2 – 924.3)	(18.1 – 51.3)	(494.8 – 923.6)	(1.67 – 4.04)
50kHz	604.3 ± 91.0	59.2 ± 10.4	601.2 ± 91.0	5.68 ± 0.98
(418.2 – 828.2)	(35.5 – 85.8)	(414.1 – 824.6)	(3.86 – 7.95)
250kHz	543.6 ± 84.8	46.0 ± 7.0	542.5 ± 84.9	4.88 ± 0.52
(360.4 – 747.2)	(30.8 – 60.6)	(361.0 – 746.8)	(3.92 – 6.10)
500kHz	526.0 ± 82.7	-	-	-
(345.6 – 723.6)
1000kHz	513.5 ± 80.8	-	-	-
(334.9 – 709.9)
*ImpediMed DF50*	Z (Ω)	Xc (Ω)	R (Ω)	PhA (°)
50kHz	545.4 ± 85.4	59.5 ± 10.9	542.1 ± 85.4	6.34 ± 1.15
(372.0 – 745.1)	(34.5 – 86.8)	(367.7 – 741.1)	(4.00 – 9.25)
*ImpediMed SFB7*	Z (Ω)	Xc (Ω)	R (Ω)	PhA (°)
5kHz	627.6 ± 91.9	30.6 ± 6.9	626.8 ± 91.8	2.82 ± 0.62
(455.8 – 850.9)	(16.0 – 47.5)	(455.4 – 850.0)	(1.80 – 4.65)
50kHz	548.3 ± 86.0	57.1 ± 10.6	545.5 ± 85.9	6.03 ± 1.11
(374.5 – 749.5)	(32.4 – 79.2)	(370.5 – 745.7)	(3.90 – 8.50)
250kHz	490.1 ± 80.0	32.2 ± 5.7	489.0 ± 80.0	3.80 ± 0.58
(321.8 – 675.7)	(17.3 – 42.0)	(320.6 – 674.5)	(2.50 – 5.10)
500kHz	477.1 ± 78.2	16.0 ± 5.1	476.8 ± 78.2	1.94 ± 0.59
(311.5 – 659.8)	(5.0 – 29.2)	(311.2 – 659.2)	(0.50 – 3.60)
1000kHz	475.4 ± 78.2	−1.9 ± 8.9	475.3 ± 78.1	−0.23 ± 1.06
(310.3 – 655.5)	(−24.7 – 20.8)	(310.3 – 655.3)	(−2.50 – 2.70)

[i] Note. Z = impedance, Xc = reactance, R = resistance, PhA = phase angle. Data are presented as mean ± standard deviation and (range).

Table 3.

Whole-body within-session intra-device reliability at 5 kHz.

	Z	Xc	R	PhA
*InBody 970*
ICC_2,1	0.997 (0.993, 0.998)	0.989 (0.964, 0.995)	0.997 (0.993, 0.998)	0.993 (0.985, 0.996)
CV	0.66%	1.75%	0.66%	1.50%
SEM	4.44Ω	0.51Ω	4.44Ω	0.04°
MDC	12.31Ω	1.41Ω	12.31Ω	0.11°
MAD	3.88Ω	0.56Ω	3.85Ω	0.03°
p-value	< 0.001	< 0.001	< 0.001	< 0.001
*InBody 770*
ICC_2,1	0.999 (0.997, 0.999)	0.992 (0.987, 0.995)	0.999 (0.997, 0.999)	0.993 (0.990, 0.995)
CV	0.39%	1.79%	0.39%	1.64%
SEM	2.65Ω	0.55Ω	2.65Ω	0.04°
MDC	7.35Ω	1.52Ω	7.35Ω	0.11°
MAD	2.49Ω	0.32Ω	2.48Ω	0.02°
p-value	< 0.001	< 0.001	< 0.001	0.01
*SFB7*
ICC_2,1	1.00 (1.00, 1.00)	0.999 (0.999, 1.00)	1.00 (1.00, 1.00)	0.998 (0.997, 0.998)
CV	0.08%	0.53%	0.08%	1.05%
SEM	0.49Ω	0.16Ω	0.49Ω	0.03°
MDC	1.36Ω	0.44Ω	1.36Ω	0.08°
MAD	0.14Ω	0.06Ω	0.13Ω	0.005°
p-value	0.06	0.01	0.07	0.23

[i] Note. Z = impedance, Xc = reactance, R = resistance, PhA = phase angle, ICC = intraclass correlation coefficient, CV = coefficient of variation, SEM = standard error of the measurement, MAD = mean absolute difference. P-values are presented for pairwise comparisons between trials one and two for each variable and correspond with MAD but are not interpreted on their own as direct measures of agreement. The threshold for statistical significance set at p < 0.05.

Table 4.

Whole-body within-session intra-device reliability at 50 kHz.

	Z	Xc	R	PhA
*InBody 970*
ICC_2,1	0.999 (0.997, 0.999)	0.997 (0.994, 0.999)	0.999 (0.997, 0.999)	0.998 (0.997, 0.999)
CV	0.48%	0.77%	0.48%	0.77%
SEM	2.86Ω	0.45Ω	2.86Ω	0.04°
MDC	7.93Ω	1.25Ω	7.93Ω	0.11°
MAD	2.49Ω	0.38Ω	2.46Ω	0.01°
p-value	< 0.001	< 0.001	< 0.001	0.07
*InBody 770*
ICC_2,1	0.999 (0.998, 1.00)	0.998 (0.996, 0.998)	0.999 (0.998, 1.00)	0.998 (0.997, 0.998)
CV	0.38%	0.87%	0.38%	0.86%
SEM	2.30Ω	0.52Ω	2.30Ω	0.05°
MDC	6.38Ω	1.44Ω	6.38Ω	0.14°
MAD	1.82Ω	0.13Ω	1.81Ω	0.006°
p-value	< 0.001	0.09	< 0.001	0.38
*DF50*
ICC_2,1	0.999 (0.999, 1.00)	0.996 (0.995, 0.997)	0.999 (0.999, 1.00)	0.986 (0.981, 0.990)
CV	0.35%	1.08%	0.37%	2.15%
SEM	1.91Ω	0.64Ω	2.00Ω	0.14°
MDC	5.29Ω	1.77Ω	5.54Ω	0.39°
MAD	0.51Ω	0.08Ω	0.48Ω	0.01°
p-value	0.07	0.39	0.10	0.53
*SFB7*
ICC_2,1	0.999 (0.999, 0.999)	1.00 (1.00, 1.00)	1.00 (1.00, 1.00)	0.996 (0.995, 0.997)
CV	0.45%	0.30%	0.07%	1.10%
SEM	2.46Ω	0.17Ω	0.39Ω	0.07°
MDC	6.82Ω	0.47Ω	1.08Ω	0.19°
MAD	0.63Ω	0.05Ω	0.13Ω	0.01°
p-value	0.08	0.048	0.02	0.22

Table 5.

Whole-body within-session intra-device reliability at 250 kHz.

	Z	Xc	R	PhA
*InBody 970*
ICC_2,1	0.999 (0.997, 0.999)	0.995 (0.993, 0.997)	0.999 (0.997, 0.999)	0.992 (0.988, 0.994)
CV	0.51%	1.02%	0.51%	1.01%
SEM	2.77Ω	0.46Ω	2.77Ω	0.05°
MDC	7.68Ω	1.28Ω	7.68Ω	0.14°
MAD	2.29Ω	0.09Ω	2.29Ω	0.01°
p-value	< 0.001	0.17	< 0.001	0.09
*InBody 770*
ICC_2,1	0.999 (0.998, 0.999)	0.990 (0.986, 0.993)	0.999 (0.998, 0.999)	0.980 (0.972, 0.986)
CV	0.42%	1.51%	0.43%	1.46%
SEM	2.30Ω	0.70Ω	2.31Ω	0.07°
MDC	6.38Ω	1.94Ω	6.40Ω	0.19°
MAD	1.76Ω	0.12Ω	1.77Ω	0.03°
p-value	< 0.001	0.22	< 0.001	0.01
*SFB7*
ICC_2,1	1.00 (1.00, 1.00)	0.995 (0.992, 0.996)	1.00 (1.00, 1.00)	0.990 (0.985, 0.993)
CV	0.13%	1.31%	0.12%	1.57%
SEM	0.63Ω	0.42Ω	0.61Ω	0.06°
MDC	1.75Ω	1.16Ω	1.69Ω	0.17°
MAD	0.08Ω	0.003Ω	0.08Ω	0.006°
p-value	0.37	0.96	0.37	0.47

Table 6.

Whole-body within-session intra-device reliability at 500 kHz.

	Z	Xc	R	PhA
*InBody 970*		-	-	-
ICC_2,1	0.999 (0.997, 0.999)
CV	0.53%
SEM	2.78Ω
MDC	7.71Ω
MAD	2.27Ω
p-value	< 0.001
*InBody 770*		-	-	-
ICC_2,1	0.999 (0.998, 0.999)
CV	0.44%
SEM	2.30Ω
MDC	6.38Ω
MAD	1.80Ω
p-value	< 0.001
*SFB7*
ICC_2,1	1.00 (1.00, 1.00)	0.976 (0.967, 0.983)	1.00 (1.00, 1.00)	0.968 (0.956, 0.977)
CV	0.07%	4.9%	0.07%	5.41%
SEM	0.32Ω	0.78Ω	0.33Ω	0.10°
MDC	0.89Ω	2.16Ω	0.91Ω	0.28°
MAD	0.25Ω	0.17Ω	0.25Ω	0.02°
p-value	< 0.001	0.15	< 0.001	0.22

Table 7.

Whole-body within-session intra-device reliability at 1000 kHz.

	Z	Xc	R	PhA
*InBody 970*		-	-	-
ICC_2,1	0.999 (0.997, 0.999)
CV	0.51%
SEM	2.62Ω
MDC	7.26Ω
MAD	2.14Ω
p-value	< 0.001
*InBody 770*		-	-	-
ICC_2,1	0.999 (0.998, 0.999)
CV	0.46%
SEM	2.34Ω
MDC	6.49Ω
MAD	1.85Ω
p-value	< 0.001
*SFB7*
ICC_2,1	1.00 (1.00, 1.00)	0.968 (0.955, 0.977)	1.00 (1.00, 1.00)	0.961 (0.945, 0.972)
CV	0.14%	−83.39%	0.14%	−92.05%
SEM	0.66Ω	1.16Ω	0.65Ω	0.21°
MDC	1.83Ω	3.22Ω	1.80Ω	0.58°
MAD	0.68Ω	0.13Ω	0.66Ω	0.01°
p-value	< 0.001	0.60	< 0.001	0.79

[i] Note. Z = impedance, Xc = reactance, R = resistance, PhA = phase angle, ICC = intraclass correlation coefficient, CV = coefficient of variation, SEM = standard error of the measurement, MAD = mean absolute difference. CV values for SFB7 Xc and PhA at 1000kHz are shown for completeness but may not be interpretable as the corresponding mean values were near zero or negative. P-values are presented for pairwise comparisons between trials one and two for each variable and correspond with MAD but are not interpreted on their own as direct measures of agreement. The threshold for statistical significance set at p < 0.05.

Table 8.

Simple slope moderation analysis results for age.

	Condition	B	95% CI	p-value
InBody 770	−1SD Age	1.019	0.959, 1.079	< 0.001
250kHz – PhA	+1SD Age	0.927	0.869, 0.984	< 0.001
	Average	0.973	0.934, 1.011	< 0.001
ImpediMed DF50	−1SD Age	0.997	0.989, 1.010	< 0.001
50kHz – Z	+1SD Age	1.010	1.001, 1.020	< 0.001
	Average	1.004	0.998, 1.010	< 0.001
ImpediMed DF50	−1SD Age	0.998	0.988, 1.007	< 0.001
50kHz – R	+1SD Age	1.011	1.002, 1.020	< 0.001
	Average	1.004	0.998, 1.011	< 0.001
ImpediMed SFB7	−1SD Age	0.988	0.981, 0.995	< 0.001
50kHz – Xc	+1SD Age	1.000	0.993, 1.007	< 0.001
	Average	0.994	0.990, 0.999	< 0.001
ImpediMed SFB7	−1SD Age	1.001	1.000, 1.001	< 0.001
500kHz – Z	+1SD Age	0.999	0.997, 1.000	< 0.001
	Average	1.000	0.999, 1.001	< 0.001
ImpediMed SFB7	−1SD Age	1.001	1.000, 1.001	< 0.001
500kHz – R	+1SD Age	0.999	0.997, 1.000	< 0.001
	Average	1.000	0.999, 1.001	< 0.001
ImpediMed SFB7	−1SD Age	1.001	0.997, 1.004	< 0.001
1000kHz - Z	+1SD Age	0.995	0.991, 0.998	< 0.001
	Average	0.998	0.995, 1.000	< 0.001
ImpediMed SFB7	−1SD Age	1.000	0.997, 1.004	< 0.001
1000kHz - R	+1SD Age	0.995	0.991, 0.998	< 0.001
	Average	0.998	0.995, 1.000	< 0.001

[i] Note. Z = impedance, R = resistance, Xc = reactance, PhA = phase angle, SD = standard deviation.

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DOI: https://doi.org/10.2478/joeb-2026-0010 | Journal eISSN: 1891-5469

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Language: English

Page range: 67 - 77

Submitted on: May 3, 2026

Published on: Aug 8, 2026

Published by: University of Oslo

In partnership with: Paradigm Publishing Services

Keywords:

Bioimpedance,

current,

voltage

Related subjects:

Engineering,

Bioengineering and biomedical engineering,

Biomedical electronics,

Life sciences,

Biophysics,

Medicine,

Biomedical engineering,

Physics,

Spectroscopy and metrology

© 2026 Kworweinski Lafontant, David H. Fukuda, Sofea Smith, Jack Livingston, Michelle Da Silva Barbera, Ngoc Linh Nhi Nguyen, Edwin Rodriguez-Cruz, Susan Kampiyil, Katie R. Hirsch, Sarah K. Fretti, Jeffrey R. Stout, published by University of Oslo
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 17 (2026): Issue 1 (January 2026)

Examining within-session test-retest reliability of four bioimpedance devices among adults across a wide age range

Figures & Tables

Figure 1.

Figure 2.

Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6.

Table 7.

Table 8.

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