Joined: 07 Nov 2005 Posts: 1105 Location: The Netherlands at Hole 19
Please take some time to read the document behind the link. It explains in detail, including examples, what P and U do. In the example with U you will notice the GN call issues unqualified SSA's for PATIENT and ILLNESS (parentage was established by the prior GU all with qualified SSA's). Normally the GN call would move positioning but the U command code prevents this. The GN call in the example will be satified until there's no TREATMNT segment found under this PATIENT/ILLNESS resulting in status code GE.