Reliability and Validity of an Ultrasonic Device for Measuring Height in Adults

BACKGROUND: The ultrasonic stadiometer was originally developed as a device to measure and monitor children’s height. However, an ultrasonic stadiometer (InLab S50; InBody Co., Seoul, Korea) was used to measure adults’ height in the 2018 Korea Community Health Survey (KCHS). This study was conducted to assess the reliability and validity of the InLab S50 in adults. METHODS: The study subjects were 120 adults (reliability test, n=20; validity test, n=100) who had visited a health screening center. The intra- and inter-rater reliabilities of InLab S50 were assessed using the intraclass correlation coefficient (ICC). The agreement between InLab S50 and an automatic stadiometer (HM-201; Fanics, Busan, Korea) was assessed using Pearson’s correlation coefficient and Bland-Altman analysis. RESULTS: The intra- and inter-rater reliabilities of the InLab S50 were excellent (ICC=0.9999 and 0.9998, respectively). The correlation coefficient of the height measured by the two measurement devices was very high (r=0.996). The difference (Δheight [HM-201-InLab S50]) was -0.15±0.78 cm (95% limit of agreement [LOA], -1.69 to 1.38). After excluding the values outside 95% LOA, the difference was further reduced to -0.05±0.59 cm (95% LOA, -1.20 to 1.10). CONCLUSION: This study showed that the InLab S50 is a reliable and valid device for the measurement of adults’ height. Therefore, we think that InLab S50 could be used to measure adults’ height in household health surveys such as the KCHS.