FDA grants De Novo marketing authorization for Rho
Silver Spring, Maryland. The US Food and Drug Administration granted De Novo authorization for Rho, creating a new device category: radiology software for opportunistic evaluation of low bone mineral density.
The De Novo order, granted on April 9, 2024, classifies Rho as a Class II device under a new regulation, 21 CFR 892.1171, “Radiology software for opportunistic evaluation of low bone mineral density.” Rho had earlier received Breakthrough Device designation.
The authorized indication: Rho is intended for use opportunistically with standard frontal radiographs of the lumbar spine, thoracic spine, chest, pelvis, knee or hand and wrist in patients aged 50 and older. It provides a notification, in the form of a report, to aid radiologists and physician interpreters in identifying patients with possible low bone mineral density at L1 to L4 or the femoral neck, to prompt a clinical assessment of bone health. Rho should not be used to rule out low bone mineral density.
The FDA’s decision summary reports specificity of 0.90 to 0.94 and areas under the curve of 0.82 to 0.88 across three test datasets from Canada and the United States.
In September 2025 the FDA cleared the first follow-on device in the category, citing Rho as its predicate.