If You Change It, FDA Will Come: What the O.N. Diagnostics Warning Letter Means for SaMD Modifications By Jennifer D. Newberger —

https://www.thefdalawblog.com/2026/10/if-you-change-it-fda-will-come-what-the-o-n-diagnostics-warning-letter-means-for-samd-modifications/?utm_source=rss&utm_medium=rss&utm_campaign=if-you-change-it-fda-will-come-what-the-o-n-diagnostics-warning-letter-means-for-samd-modifications Yes, we know — the O.N. Diagnostics Warning Letter has already been thoroughly covered since FDA posted it on October 6. We waited for the dust to settle, since we think software companies will be living with the implications of this letter for quite some time. Though posted on October 6, FDA issued the letter to O.N. Diagnostics on September 1, 2026, following a March 12–17, 2026, inspection of its VirtuOst and VirtuOst Vertebral Fracture Assessment (VFA) software products. VirtuOst VFA was originally cleared under K171435 to use sagittal sections of a spine CT to visualize vertebral deformities, classify fracture type and grade, and support physician management of osteoporosis. The letter provides perhaps the clearest perspective on where FDA will draw the line between the kind of software iteration that lives comfortably inside an existing clearance and the kind that requires a new submission — and it is one that will likely not sit well with SaMD manufacturers who have been treating model retraining and architecture changes as internal engineering decisions.