Medical professionals fear patients may defer an in-person check-up because of faulty results on a mobile app. By the time they see a doctor, it may be too late.

A smartphone app that rids you of acne. Another that monitors your heart rate 24/7. One that detects skin cancer by looking at your birthmarks. If they sound too good to be true, they may be.

Patients today use a number of apps that purport to track and treat a panoply of ailments, a headache for regulators and patient safety advocates. Now, the advent of wearable devices bris-tling with sophisticated biotracking sensors is stirring concern in the medical community about misdiagnoses that could have serious consequences for consumers.

Some are asking whether Apple and Google should do more to police their fast-growing app marketplaces.

“Most of the health apps out there are built by people with zero medical experience,” said Paris Wallace, chief executive officer of Ovuline, a popular fertility app. Worse, many developers do not have the resources for legal counsel, Wallace said, and are more likely to make false claims to patients without seeking FDA clearance.

If patients perceive a mobile app as a cheaper alternative to a trip to my office, that’s worrying

The Food and Drug Administration last year published guidelines on the kinds of mobile apps it will supervise. But industry insiders fear the agency may get overwhelmed as apps mushroom.

Last week, Samsung Electronics launched a health platform for third-party developers, SAMI and Apple introduced HealthKit, a repository of data for medical apps that opens up new realms for developers to explore. It may also make it easier for those with scant understanding of regulatory protocols to dive into the market.

Health apps are big business for Apple and Google, the two leading app marketplaces. The iPhone maker is the preferred choice for developers. Analytics firm AppAnnie found that Apple generates five times more revenue from downloads of health and fitness apps than Google.

How the two companies, who both declined to comment for this story, will handle the proliferation of medical apps is unclear. One source familiar with the matter said Apple is seeking to add a regulatory expert to its growing digital health team, who will be tasked with oversight of the App Store.

Research has shown that many existing medical apps may be useless. Seventy-five per cent of smartphone apps that claim to assess malignancy are wrongly diagnosing at least 30 per cent of melanomas as ‘unconcerning’, researchers from the American Medical Association’s Jama Dermatology found.

A 2012 study by the New England Centre for Investigative Reporting revealed that of 1,500 health apps it evaluated, 20 per cent claimed to treat or cure medical problems, but only a small percentage of them had actually been clinically tested.

Medical professionals fear patients may defer an in-person check-up because of faulty results. By the time they see a doctor, it may be too late. A false negative for cancer, for instance, may prompt a user to put off professional consultation.

“If patients perceive a mobile app as a cheaper alternative to a trip to my office, that’s worrying,” said Molly Maloof, a physician who has spoken about such matters and is a consultant for digital-health start-ups like Sano Intelligence and GeneSolve.

Echoing a familiar Silicon Valley stance, developers argue that increased federal oversight will only stifle innovation.

Mike Lee, co-founder of MyFitnessPal, a weight-loss app that claims 50 million users, said his company wouldn’t exist today if it been required to seek regulatory approval.

Patient safety advocates counter that the FDA’s concern shouldn’t be to appease Silicon Valley’s entrepreneurs but to protect consumers. Moreover, apps like MyFitnessPal are focused on wellness and would not require FDA approval.

Policymakers are struggling to keep up. The FDA lacks the resources to monitor each and every one of these apps.

According to an IMSHealth report from October 2013, more than 43,000 health-related apps are available on the US iTunes store, and 33,500 on Google Play. Bradley Merrill Thompson, a health-care-focused attorney with Washington DC-based Epstein, Becker & Green, speculates that hundreds of unregulated mobile ‘medical devices’ – anything with a specific medical application – populate Apple’s store.

Reuters found several dozen applications on the App Store and Google Play that fall into the FDA’s definition of a medical device. The products have not been cleared by the feds, and offer little or no clinical evidence to back up their claims.

“FDA intends to exercise enforcement discretion for most mobile apps that meet the definition of device,” an FDA spokeswoman said.

The FDA has cracked down on a small number of mobile medical apps in recent years.

Some say Apple and Google should give them a hand. Apple, for instance, has no qualms about banning apps with explicit or illegal content.

If these companies are not more proactive, “nothing will be remedied until bodies start piling up”, said Christopher Dolan, a personal injury lawyer with the Dolan Law Firm in San Francisco.

To avoid liability, developers typically include disclaimers in their terms of use.

But these are often buried in the fine print.

In September 2013, the FDA clarified that it will focus on apps that seek to replace a doctor’s visit or perform clinical tests.