One of the main points of our article was to highlight the differences in the regulatory burden on devices that couple a smartphone app to external hardware when compared with the apparent lack of such a burden on devices using only the onboard internal hardware of a smartphone.2 Our conclusion was that the latter category of smartphone app–based medical devices is most in need of validation studies from the medical community because this category is readily available to our patients, yet it escapes the regulation to which all other medical devices must submit. To that end, we previously published a validation study showing that 4 popular iPhone app-based vital sign monitors available to consumers had poor correlation to actual vital sign monitors.3
In summary, although noninvasive glucose monitoring devices would have significant benefits for patients, it appears that there are substantial technological problems that would need to be solved before they reach similar efficacy to invasive monitors. Fortunately, the FDA is an ally with them in protecting patients from inaccurate or dangerous devices. It will require the expertise and passion of many other providers to protect our patients from the unfounded and unvalidated claims of other manufacturers. This is especially so when manufacturers target the gaps in FDA medical device regulation, such as with smartphone app-based medical devices that do not utilize external hardware.