FDA issues "How to find and effectively use Predicate Devices" which states primary predicate is a must

An update was posted by the FDA on "How to find and effectively use Predicate Devices". This update stated that "Manufacturers must identify a primary predicate device which is most similar to the device under review with respect to indications for use and technological characteristics" and that "the use of split predicates is inconsistent with the 510(k) regulatory standard".