In one of my projects at NJIT, my group member and I were tasked to come up with an innovative medical device as a final project. What we had decided on was a wearable device that had the ability to measure blood-glucose levels while relaying the obtained data to a mobile app on the patient’s phone. In the beginning, were very confused on what classification this idea would fall under. After all, it did not seem to fit any one of the three main classes generally discussed so it was initially decided that no FDA regulation would be required. After doing some research, we too had discovered as previously mentioned by djr32 in an above response, that our product would be classified as a mobile medical application. This is because we had both a medical device actively measuring and relaying the data to application located on the patients phone which would display the data in an organized way.

https://www.fda.gov/MedicalDevices/DigitalHealth/MobileMedicalApplications/ucm368744.htm