Smartphone apps are inching onto the turf of doctors and medical-device makers, promising to measure heart rates, display X-ray images and detect skin cancer—and prompting concerns about how well they work and whether consumers may rely on their smartphones and skip seeing a doctor. The accuracy of such apps can vary significantly. Researchers at the University of Pittsburgh Medical Center evaluated four smartphone apps meant to determine whether moles have morphed into cancerous melanomas. The best-performing app accurately identified cancerous moles 98.1% of the time, while the worst picked them up only 6.8% of the time, according to the study. Two scored in the neighborhood of 70%. That’s far worse than trained dermatologists with modern equipment, who can accurately spot about 90% of melanomas on the first try, according to other studies, though it compared well with the detection skills of unspecialized family doctors. The study, published online by JAMA Dermatology, used the four unidentified apps to analyze images of 188 moles, including 60 melanomas, that had already been evaluated by a dermatologist. Three of the apps—priced at $5 or less—used algorithms to analyze moles. The worst-performing app suggested dozens of swollen, discolored cancers were benign. The app with the best results relied on doctors, forwarding images to board-certified dermatologists for review at a cost of $5 per mole/ This type of “telemedicine” is a growing field of medical image analysis from a distance rather than a true computer software application. About one-third of adult Americans used online resources, including apps, to diagnose a health problem. About 41% of those people said the diagnosis was later confirmed by a medical professional. Unlike medical devices, which need to be approved by the Food and Drug Administration, most apps haven’t yet been required to demonstrate their safety and efficacy.