An iPhone application that lets users check levels of blood, protein and other substances in their urine is the first target of U.S. regulators seeking boundaries in a burgeoning industry for medical diagnosis on-the-go.

Biosense Technologies Private Ltd.’s uChek system isn’t cleared by the Food and Drug Administration and the agency said it wants to know why not, in a first-of-its-kind letter to a maker of a mobile-device application. The app relies on users, such as diabetics checking their glucose, to dip test strips in urine and use the smartphone’s camera to allow the system to processes and generate automated results.

“When these dipsticks are read by an automated strip reader, the dipsticks require new clearance as part of the test system,” the FDA said in a letter sent to the firm.

UChek works with test strips made by Siemens AG and Bayer AG, which are only approved for visual reading and require new clearance for automated analysis, the FDA said. The agency has said it wants stricter rules for apps that directly diagnose or treat conditions, proposing in 2011 to apply similar quality standards as for heart stents, ultrasound machines and other medical devices.

“We intend to finalize the guidance this year,” Synim Rivers, an agency spokeswoman, said in an email. “The FDA has proposed a regulatory approach that limits its immediate oversight to a specific, small subset of mobile medical applications that are medical devices and present the greatest risk to patient safety if they don’t work as intended.”

The app needed to run the $40 automated system became available in Apple Inc.’s App Store earlier this year after being touted at the technology conference TED2013 at the end of February in California. The FDA told Biosense the company may need to gain agency clearance for the entire system, including the strips.

Biosense Response

“We intend to work very closely with the U.S. FDA over the coming months to ensure that we continue to deliver accurate, affordable and convenient diagnostics across the world,” Abhishek Sen, co-founder of Thane, India-based Biosense, wrote in an email.

Biosense declined to comment further on their communication with the FDA other than to say it received the letter May 22. Representatives from Siemens and Bayer, both based in Germany, didn’t immediately respond to requests for comment.

The FDA for the first time sent a letter to an app maker notifying them of the agency’s concerns about providing an opportunity for Biosense to meet and discuss the issue.

“Please note that though the types of urinalysis dipsticks you reference for use with your application are cleared, they are only cleared when interpreted by direct visual reading,” the letter says.

“Since your app allows a mobile phone to analyze the dipsticks, the phone and device as a whole functions as an automated strip reader. When these dipsticks are read by an automated strip reader, the dipsticks require new clearance as part of the test system. Therefore, any company intending to promote their device for use in analyzing, reading, and/or interpreting these dipsticks need to obtain clearance for the entire urinalysis test system (i.e., the strip reader and the test strips, as used together).”

Depending on how a company responds, the FDA may follow up with a warning letter that sets out specific violations of the law that must be addressed immediately, Rivers said.

The FDA letter points to data submitted for a urine analyzer made by Acon Laboratories Inc. as an example of the information sought from Biosense. Acon, based in San Diego, submitted a 510(k) application, which is the least stringent of FDA device approval pathways that doesn’t typically warrant clinical trials and only requires a company prove their product is similar to one on the market.

The full text of the FDA letter can be read online.

(Bloomberg news contributed to this report.)