O.N. Diagnostics, LLC – FDA Warning Letter, Mar 17, 2026

O.N. Diagnostics, LLC, located in Berkeley, California, received a formal warning from the FDA following an inspection conducted between March 12 and March 17, 2026. The agency determined that the company is marketing an unauthorized version of its VirtuOst Vertebral Fracture Assessment (VFA) software, which is used to diagnose osteoporosis and spinal fractures. Specifically, version 3.0.0 of the software introduced a new machine learning algorithm and transitioned to a web-based architecture without the required FDA clearance. These modifications introduce potential risks to diagnostic accuracy and cybersecurity that have not been adequately validated. The FDA also identified significant failures within the company’s quality management system. Specifically, the firm failed to take timely corrective actions to resolve known software issues, some of which remained unaddressed for over three years. Furthermore, the company’s procedures for monitoring suppliers and reporting adverse events to the FDA were found to be deficient or non-compliant with federal safety regulations. Under the Federal Food, Drug, and Cosmetic Act, these products are considered illegally marketed and potentially unsafe. The FDA has ordered O.N. Diagnostics to immediately stop the commercial distribution of the unauthorized software. The company must provide a written response within 15 business days detailing the specific steps taken to correct these violations and a comprehensive plan to prevent future occurrences. Failure to comply could lead to further regulatory action, including product seizures, legal injunctions, or financial penalties.