Operating principle

In FDA's 510(k) change guidance, a change in operating principle is a significant technological change that needs careful assessment and often a new 510(k). In substantial equivalence reviews, a different operating principle can raise different questions of safety and effectiveness.

The mode of operation or mechanism of action through which a device fulfills (or achieves) its intended use. An example of a change in operating principle would be using a new algorithm to compress images in a picture archiving and communications system. For an IVD, an example would be a change from immunofluorescence to ELISA.

FDA guidance: Deciding When to Submit a 510(k) for a Change to an Existing Device (October 2017), Appendix C, Significant Terminology