Table 1

Technical error of measurement between two repeat measurements for anthropometric measures for body sizes in children with special needs 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)
 Supine length (cm)25126.00.3 (−1.1 to 1.8)0.62.47 (1.96)
 Weight (kg)2631.3−0.2 (0.6 to 0.3)0.50.75 (2.39)
 Body mass index (kg/m2)2319.3−0.2 (−0.9 to 0.5)0.61.38 (6.87)
 True waist circumference (cm)*2670.00.05 (−1.0 to 1.1)0.91.82 (2.60)
 Umbilical waist (cm)2668.3−6.3 (−1.4 to 0.8)0.61.83 (2.70)
Standers (n=23)
 Standing height (cm)22144.9−0.32 (−0.6 to 0.0)0.040.55 (0.38)
 Weight (kg)2350.6−0.09 (−0.5 to 0.3)0.60.59 (1.18)
 Body mass index (kg/m2)2222.00.04 (−0.2 to 0.2)0.70.31 (1.44)
 True waist circumference (cm)*1780.0−0.02 (−1.4 to 1.4)1.01.86 (2.33)
 Umbilical waist (cm)1776.0−0.7 (−2.2 to 0.8)0.32.04 (2.68)
  • Body mass index: for standers=weight/height2, for non-standers=weight/supine length2; CV: 100x TEM/mean of measurements taken, expressed as a percentage. Difference in means P value assessed by paired t test. TEM =√∑d2⁄2 n, where d is difference between two measurements and n is number of measurements.

  • *True waist circumference - measured midway between the 10th rib and the iliac crest.

  • CV, coefficient of variability.