Used by clinical applications to send an order to the pharmacy and/or dispensing systems. It may be sent as either an order containing a single pharmacy/treatment order for a patient or as an order containing multiple pharmacy/treatment orders for a patient (e.g., 1 mg tablet of Aspirin, 0.5 mg 0.5% Albuterol).

The transmission of orders occurs between the clinical application placing the order (the placer) and the clinical application filling the order (the filler). Typically, the clinician (e.g., physician) is entering orders on the HIS application which acts as the placer application in HL7 parlance. The system to which the order is targeted (e.g., the lab in the case of a complete blood count order) is the filler of the order.

The three RDE messages include Pharmacy encoded order messages:

• RDE-001 - ORM - Order message (also RDE, RDS, RGV, RAS)
• RDE-011 - RDE - Pharmacy/treatment encoded order
• RDE-025 - RDE - Pharmacy/treatment refill authorization request

The segments and groups of segments in the RDE message are as follows, and apply for all trigger events:

In HL7 pipe and hat format, the RDE message would look like this: