4.1.2.1 filler: the application responding to, i.e., performing, a request for services (orders) or producing an observation. The filler can also originate requests for services (new orders), add additional services to existing orders, replace existing orders, put an order on hold, discontinue an order, release a held order, or cancel existing orders.
4.1.2.2 observation segment: an OBX segment defined in Chapter 7.
4.1.2.3 order: a request for a service from one application to a second application. The second application may in some cases be the same; i.e., an application is allowed to place orders with itself.
4.1.2.4 order detail segment: one of several segments that can carry order information. Examples are OBR and RXO. Future ancillary-specific segments may be defined in subsequent releases of the Standard if they become necessary.
4.1.2.5 placer: the application or individual originating a request for services (order).
4.1.2.6 placer order group: a list of associated orders coming from a single location regarding a single patient.