Method of Measuring the Accuracy and Reliability of a Medical Device

Dear Editor, We read an article in the recent edition of your journal that aimed to “measure the body composition of Indian adults using the Karada scan Omron HBF-701 model.”[1] In this study, the authors recruited research participants and measured their body fat and related parameters with a body fat monitor and concluded that the method of measurement is “a novel and rapid method to reliably measure the different variables of body composition” in the abstract. Further, they concluded that the method is “easy, quick, safe, and most convenient” to evaluate body composition. We would like to share some of our observations regarding the study. Authors could write the conclusion according to the aim and obtained result. The authors aimed to measure the body fat of a sample population. However, by only measuring the body fat with a device, they concluded that the device or the measurement process is a “novel,” “rapid,” “reliable,” “easy,” “safe,” and “most convenient” one to measure body fat. The adjectives used here are not supported by the evidence they got from the study. The bioelectrical impedance analysis method has been used for a long time.[2] The device used in the article has been in the market for a long time. Hence, authors could avoid the term “novel.” The accuracy of a device is the capability to measure the parameter that it is supposed to measure. Reliability is the capability of the device to produce the same result in repeated measurements.[3] In the study, neither the accuracy was checked nor the reliability was checked. Rapidity of measurement with another method, ease of measurement, safety of the device, or convenience level comparison were also mentioned without any measured attributes. In Figure 1, we present the brief method of testing the accuracy and reliability of a device. In accuracy, the same parameter is measured by the device of interest and gold standard method and compared. In reliability, the same parameter is measured more than once by the device and the repeated measurements are compared with each other. One interesting fact is that a device may be reliable (producing the same result in repeated measures) but not accurate (does not measure what it is supposed to measure). Hence, measuring accuracy is of utmost importance. For example, two glucose monitors were available in the market. However, when their accuracy was tested, they failed to show the desired level of accuracy.[4] Hence, post-marketing surveillance accuracy is needed for devices used for health care.Figure 1: Method of measuring accuracy and reliability by comparing with gold standard and by repeated measures, respectivelyData availability statement Nil. Details of contribution Himel Mondal: Concept and design, Literature search, Visualization, Drafting Manuscript. Shaikat Mondal: Concept, Literature search, Editing manuscript. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.