When sending and receiving orders and results using the HL7 standard (HL7 v2.x), there are two identification numbers that are typically required. In HL7 terms, they are the Placer Order Number and the Filler Order Number. These numbers have distinct uses and can be represented in two different places in the Order and Result messages.
The Placer is the person or service that requests or places the order for an observation. Examples of placers include the physician, the practice, clinic, or ward service, that orders a lab test, X-ray, vital signs.
Typically, the order message (ORM) used to request the observation will contain a Placer Order Number in field 2 of the ORC segment (ORC-2) and/or in field 2 of the OBR segment (OBR-2). A requisition number is an example of a Placer Order Number. It uniquely identifies an order among all orders from a particular ordering application.
The ORC-2 Placer Order Number field contains the same information as OBR-2 Placer Order Number field. If the placer order number is not present in the ORC, it must be present in the associated OBR and vice versa. If there is a value in the ORC-2 and OBR-2, they must be the same. Note that in the ORM message, the OBR segment is optional, plus the message may contain multiple orders for which the rules still apply.
The following is an HL7 messaging example of the ORC and OBR segments from an ORM message with the Placer Order Number in ORC-2 and OBR-2:
ORC|NW|2156286|||||||20060221061809|^MOUSE^MINNIE^A^^^RN||TBU^BUTLER JR MD^THOMAS^E^^^|||||CLINIC
OBR|1|2156286||MRSHLR-C^MR Shoulder right wo/contrast|||||||||R/O RCT VS TENDONITIS|||TBU^BUTLER JR MD^THOMAS^E^^^||…
Filler is synonymous to Producer in ASTM terminology. The Producer is the person, or service, who produces the observations (fills the order) requested by the requestor. Fillers include diagnostic services and clinical services and care providers who report observations about their patients. For example, a clinical laboratory is a producer of lab test results (filler of a lab order), and a nursing service is the producer of vital signs observations (the filler of orders to measure vital signs).
In reporting the observations, the Producer sends a Filler Order Number in ORC-3 and/or OBR-3. An accession number is an example of a filler order number that is returned in the observation message (ORU). This string uniquely identifies the order from other orders in a particular filling application.
The ORC-3 Filler Order Number field contains the same information as the OBR-3 Filler Order Number field. If the filler order number is not present in the ORC, it must be present in the associated OBR, because the ORC segment is optional in the Order Group of an ORU message.
The following is an HL7 messaging example of the ORC and OBR segments from an ORU message with the Filler Order Number in ORC-3 and OBR-3.
ORC|RE|2156286|A140875||||||20060221061809|^MOUSE^MINNIE^^^^RN||TBU^BUTLER JR MD^THOMAS^E^^^|||||CLINIC
OBR|1|2156286|A140875|MRSHLR-C^MR Shoulder right wo/contrast|||20060220141000|||||…
Typically, and as the example message segments indicate, the Filler returns the Placer Order Number as well as its Filler Order Number in the ORU message. This allows the Placer to tie the results to the appropriate order.