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.