ResApp Health Limited announced that it has submitted a 510 premarket notification to the US Food and Drug Administration for SleepCheckRx, a prescription-only, software-as-a-medical- device smartphone application for at-home sleep apnoea screening. The targeted time period for review of a 510 application by the FDA is 90 days. SleepCheckRx is ResApp's easy to use smartphone application that uses clinically accurate algorithms to assess a patient's risk of obstructive sleep apnoea by analysing breathing and snoring sounds during sleep. It requires no accessories or hardware other than a smartphone to make an assessment. In a 308 patient, prospective clinical study, the SleepCheckRx algorithms were tested against an American Academy of Sleep Medicine Type II sleep study performed simultaneously in the patient's home. In the study, the algorithms identified patients with mild, moderate, and severe OSA with a sensitivity of 85%, 83% and 83%, respectively. The algorithms had a specificity of 73%, 80% and 90%, respectively. SleepCheckRx would be made available to patients via a prescription from their healthcare provider. Patients will be provided a specific code allowing them to download SleepCheckRx from the App Store, with their results uploaded to a healthcare provider portal. FDA clearance would unlock a substantial market opportunity for ResApp. It is estimated that 42 million American adults suffer from sleep disordered breathing iii and three in ten men and almost one in five women have sleep apnoeaiv . It is further estimated that 75% of SDB cases remain undiagnosedv.