A comparison of ultrasonic and mechanical stadiometry

AIM: To compare an ultrasonic height measuring device (Gulliver) with mechanical stadiometry and the classical "book and tape measure" method. METHODS: Blinded duplicate measurements of height were made on each of 14 children by a pair of observers using a stadiometer (H) and Gulliver (G). Height was measured on a further 18 children by parents and an auxologist using Gulliver and the book and tape method (TM), and the results were compared with those obtained with a single stadiometry measurement. Finally, measurement of a rigid metal box was made on 10 occasions by the three methods. RESULTS: In the group of 14 children, the mean difference (range) in height (H minus G) was +2.8 cm (+0.5 to +4.55 cm), with H giving a systematically higher value in 276 of 280 individual measurements. In the group of 18 children, height by H was greater than by G or TM in 47 of 52 individual measurements. The mean (SD) height of the box by H (61.60 (0.07) cm) was greater than by G (60.96 (0.15) cm; p < 0.001) but not TM (61.4 (0.16) cm; p > 0.05). G and TM produced three times less reliable estimations of height than H, but with a large difference in cost, and there was evidence of systematic underrecording of height by 0.5 cm with G. CONCLUSIONS: Stadiometry is precise and reproducible, and can detect true changes in height over one month periods in mid-childhood, and should remain the standard way of observing growth. The book and tape method can produce clinically acceptable quarterly estimations of height that can be performed in the home.