Following MobiHealthNews' coverage of the rare action that FDA took last week by sending a medical app developer an "It has come to our attention" letter that instructs it to seek 510(k) clearance for its urine analysis app, two readers wrote in to point out that Biosense Technologies, the maker of the app, had indeed already registered it as a Class I medical device with the FDA. The company says as much in their FAQ as we pointed out last week, but we can also now verify that claim since its registration is noted on FDA's website (read it here).

Biosense co-founder Myshkin Ingawale has also reached out to MobiHealthNews in the past few days with a statement: "We are in receipt of the letter from the US FDA," Ingawale wrote. "We intend to work very closely with the US FDA over the coming months to ensure that we continue to deliver accurate, affordable and convenient diagnostics across the world. Apart from this, we will not be commenting on any aspect of our communication with the US FDA."

In his letter to Ingawale, FDA Deputy Director James Woods made no mention of uChek's Class 1 registration, which seems like an obvious oversight.

"We have conducted a review of our files, and have been unable to identify any Food and Drug Administration (FDA) clearance number for the uChek Urine analyzer," Woods wrote. "We request that you provide us with the FDA clearance number for the uChek Urine analyzer. If you do not believe that you are required to obtain FDA clearance for the uChek Urine analyzer, please provide us with the basis for that determination."

Registration as a Class 1 is very different from getting clearance as a Class II device, of course, and the use of the word "clearance" in the letter is understood to mean the FDA found no Class II 510(k) clearance number for the app. Still, if you're going to send a public letter to the company, why not mention the fact that it registered as Class I instead?

The company's uChek system includes an iPhone app and a color-coded mat. It works with a handful of already FDA cleared test strips from Siemens and Bayer. The uChek user puts the test strip on the mat — which contains color samples to normalize lighting conditions — and then snaps a picture with their smartphone camera. The app analyzes the strip colors against the swatches on the mat, and returns data about glucose, protein, ketone levels, and more in the sample as well as diseases detected. The user can save readings and track data over time. The app is still available in the AppStore and its description states it should only be used by or with a healthcare professional.

Since the news of the FDA's letter broke, MobiHealthNews columnist and mHealth regulatory expert Bradley Merrill Thompson outlined the reasons why the action will help advance mobile health.