Table 5

Technical error of measurement between two repeat measurements of body composition using bioimpedance analysis taken 2–4 weeks apart

Number of paired measurements (n)Mean of paired measurementsDifference between
first and second measurement Mean (95% CI)
P valuesTechnical error of measurement (CV)
Non-standers (n=30)
Impedance (Ω)22878.90.05 (−34.7 to 34.8)0.9954.1 (6.16)
Fat-free mass index (kg/m2)*2112.90.67 (5.25)
Fat mass index (kg/m2)†216.460.8 (12.39)
Standers (n=23)
Impedance (Ω)16635.62.6 (−24.4 to 29.5)0.834.7 (5.45)
Fat-free mass index (kg/m2)*1616.410.53 (3.23)
Fat mass index (kg/m2)†166.650.59 (8.93)
  • Difference in means P value assessed by paired t-test. TEM=√∑d2⁄2 n, where d is difference between two measurements and n is no. of measurements. CV: %TEM=100xTEM/mean.

  • *Calculated using the equations by Houtkooper et al 1: FFM=0.61×ht2/impedance +(0.25xweight)+1.31. Fat-free mass index=fat free mass/supine length2.13

  • †Fat mass=body weight−fat-free mass. Fat mass index=fat mass/supine length2.13

  • CV, coefficient of variability.