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5 Observation Ordering

5 Observation Ordering

Jul 07, 2021

5.1 PURPOSE

The Order Entry transaction set provides for the transmission of orders or information about orders between applications that capture the order, by those that fulfill the order, and other applications as needed. An order is a request for material or services, usually for a specific patient. These services include medications from the pharmacy, clinical observations (e.g., vitals, I&Os) from the nursing service, tests in the laboratory, food from dietary, films from radiology, linens from housekeeping, supplies from central supply, an order to give a medication (as opposed to delivering it to the ward), etc.  This document focuses on tests in the laboratory.

Most orders are associated with a particular patient. However, the Standard also allows a department to order from another ancillary department without regard to a patient (e.g., floor stock), as well as orders originating in an ancillary department (i.e., any application may be the placer of an order or the filler of an order).

We refer to the person or entity who places the order as the placer. We refer to the person or entity that carries out the order as the filler (producer in ASTM terminology). In the case where the person or entity that carries out the order also requests the order, this person or entity is referred to as the filler and placer of the order. The filler may also request another application to assign a filler or placer order number.

This chapter defines the transactions at the seventh level, i.e., the abstract messages. 

In HL7 V 2.4 new message types were introduced to accommodate automated laboratory equipment.  These new message types are:

  • OMG^O19—General clinical order message.

  • ORG^O20—General clinical order acknowledgement message.

  • OML^O21—Pathology order.

  • ORL^O22—Pathology order response.

  • OUL^R21—Unsolicited pathology observation.

These new message types contain the following new segments:

  • SAC—Specimen and container details.

  • TCD—Test code details.

  • SID—Substance identifier.

For further detail on these segments refer to HL7 V2.4 chapter 13 - Laboratory Automation. These new segments, message types and trigger event codes should not be used in the Australian context unless there is mutual agreement. 

In the Australian context the following message type and trigger event codes shall be used:

  • ORM^O01 - General Order Message

  • ORU^R01 - Observation Result (Unsolicited)

  • ORR^O02 - Order Receipt

  • ACK^R01 - Acknowledgment Result (HL7 V2.4, section 7.3.1)

  • ACK^O01 - General Acknowledgement or order

5.1.1 Preface (organization of this chapter)

This chapter has a General section that describes the trigger events, message definitions, segments and examples for the specific type of order messages. The section about a type of order is organized into background and overview, message structure, and message segments (that are specific to the order class in question). Special discussions of the use of fields, segments or messages, and examples are included. Segments are introduced in order of occurrence in a message. A list of allowable values for a field is included in the body of the text, along with the field definition for easier reference.

5.1.2 Glossary

5.1.2.1 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

5.1.2.2 Observation segment:

An OBX segment defined in Section 4: Observation Reporting

5.1.2.3 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.

5.1.2.4 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.

5.1.2.5 Placer:

The application or individual originating a request for services (order).

5.1.2.6 Placer order group:

A list of associated orders coming from a single location regarding a single patient.

5.2 ORM - general order message (event O01)   

The function of this message is to initiate the transmission of information about an order. This includes placing new orders, cancellation of existing orders, discontinuation, holding, etc. ORM messages can originate also with a placer, filler, or an interested third party.

The trigger event for this message is any change to an order. Such changes include submission of new orders, cancellations, updates, patient and non-patient specific orders, etc.

The CTD segment in this trigger is used to transmit temporary patient contact details specific to this order. 

Note: the ORM message contains the the tests ordered by the placer in the OBR segment, but it has no influence on the format or presentation of the report.

 

Order Message Structure
ORM^O01^ORM_O01 General Order Message MSH [ PID Message Header [PD1] Additional Demographics [ PV1 Patient Visit [PV2] Patient Visit- Additional Info ] [{ IN1 Insurance [IN2] Insurance Additional Info [IN3 Insurance Add'l Info - Cert. } ] [GT1] Guarantor [{AL1}] Allergy Information ] { ORC Common Order OBR Order Detail Segment [CTD] Contact Data [{DG1}] Diagnosis [{OBX}] Observation/Result [{FT1}] Financial Transaction [{CTI}] Clinical Trial Identification [BLG] Billing Segment }

 

This message struct differs from the international definition in that NTE segments have been removed and for use in pathology ordering OBR has become the default order detail segment. The same message can be used for medication and diet orders where the OBR is replaced with other order detail segments.

 

The initial response to an order is usually a generic ACK^O01 indicating Acceptance of the message, but can be an application level ORR^O01 message

General Accept ACK Structure
ACK^O01^ACK General Acknowledgment MSH Message Header MSA Message Acknowledgment [ ERR ] Error

 

The Filler application responds to the Order and can potentially return further details, such as the Filler Order Number. The ORC/OBR segments are optional however. This message is usually delayed until the specimen has been collected/received and a laboratory number has been allocated. The Filler Order number is not the same as the Laboratory Number but often includes the Lab No as part of the identifier.

Order Response Message
ORR^O02^ORR_O02 General Order Acknowledgment MSH Message Header MSA Message Acknowledgment [ERR] Error [ [PID Patient Identification { ORC Common Order OBR Order Detail Segment } ]

 

5.3 OSQ/OSR- query response for order status (event Q06)  

 

Order Status Query
OSQ^Q06^OSQ_Q06 Order Status Query MSH Message Header QRD Query Definition [ QRF ] Query Filter [ DSC ] Continuation Pointer
Query Response
OSQ^Q06^OSQ_Q06 Order Status Response MSH Message Header MSA Message Acknowledgment [ERR] Error QRD Query Definition [QRF] Query Filter [ [PID] Patient Identification { ORC Common Order OBR Order Detail [{OBX}] Observation result/detail [{CTI}] Clinical Trial Identification } ] [DSC] Continuation Pointer

The QRD and QRF segments are defined in 2.1 Message Control Segments. The subject filters contained in the QRD and QRF segments describe the kind of information that is required to satisfy the request. They are defined by local agreement between the inquiring system and the ancillary system. See the Implementation Guide for detailed examples of the use of query filter fields. 4.4.3.1 Query usage notes

The Set ID fields in the various segments (including PID) are used to count the number of segments of one kind transmitted at one level of the hierarchy.

The Query Result Level field of the QRD determines the amount of data requested. See Chapter 5, Section 5.10.5.3, “QRD - original style query definition segment.” in the HL7 International V2.4 Standard.

The OSQ message is a record-oriented query that has the structure as the regular QRY message. OSQ is included here for the convenience of implementers.

5.4 ORC SEGMENT

The ORC segment is common to many order messages.   

5.4.1 ORC - common order segment

The Common Order segment (ORC) is used to transmit fields that are common to all orders (all types of services that are requested). The ORC segment is required in the Order (ORM) message. ORC is mandatory in Order Acknowledgment (ORR) messages if an order detail segment is present, but is not required otherwise.

In some cases, the ORC may be as simple as the string ORC|OK|<placer order number>|<filler order number>|<cr>.

If details are not needed for the order, the order detail segment may be omitted. For example, to place an order on hold, one would transmit an ORC with the following fields completed: ORC-1-order control  with a value of HD, ORC-2-placer order number , and ORC-3-filler order number.

In the outpatient Medicare payment setting, a HL7 pathology order relates to a single episode - instance or occurrence.  As compared to the hospital inpatient setting the request may be part of a larger episode of care and hence only the placer order number is used and not a placer group number. Generally there is more than one test per pathology request form, e.g. FBC, UE and LFT, where each test must be ordered using an ORC/OBR segment pair.  In the FBC, UE and LFT example the order would be contained in one MSH segment with 3 separate ORC/OBR pairs for each orderable request. The ORC segment contains the order identification information where the Placer Order Number identifies each order in both the ORC and OBR segments. The episode is identified by a Placer Group Number contained in the ORC segment only. For each requested test the same Placer Order Number can be used or different numbers can be allocated to each requested test. The recommended approach is that different Placer Order Numbers are used for each test ordered. The Placer Group Number links all orders for the patient episode into a single request.

There is some overlap between fields of the ORC and those in the order detail segments. These are described in the succeeding sections.

 

5.4.1.0 ORC field definitions

HL7 Attribute Table – ORC – Common Order

SEQ

LEN

DT

OPT

RP/#

TBL#

ITEM#

ELEMENT NAME

SEQ

LEN

DT

OPT

RP/#

TBL#

ITEM#

ELEMENT NAME

1

2

ID

R

N

00119

00215

Order Control

2

250**

EI

C

 

 

00216

Placer Order Number 

3

250**

EI 

C

 

 

00217

Filler Order Number 

4

250**

EI 

O 

 

 

00218 

Placer Group Number

5

2

ID

O 

N 

00038 

00219 

Order Status 

6

1 

ID 

O 

 

00121 

00220 

Response Flag

7

200 

TQ 

O 

Y 

 

00221 

Quantity/Timing 

8 

200 

CM 

O 

 

 

00222 

Parent 

9 

26

TS 

O 

 

 

00223 

Date/Time of Transaction 

10 

250 

XCN 

O 

Y 

 

00224 

Entered By 

11 

250 

XCN 

O 

Y 

 

00225 

Verified By 

12 

250 

XCN 

C*

Y 

 

00226 

Ordering Provider 

13 

80 

PL 

O 

 

 

00227 

Enterer’s Location 

14 

250 

XTN 

O 

Y/2 

 

00228 

Call Back Phone Number 

15 

26 

TS 

O 

 

 

00229 

Order Effective Date/Time 

16 

250 

CE 

O 

 

 

00230 

Order Control Code Reason 

17 

250 

CE 

O 

 

 

00231 

Entering Organization 

18 

250 

CE 

O 

 

 

00232 

Entering Device 

19 

250 

XCN 

O

 Y

 

00233 

Action By 

20 

250 

CE 

O 

 

00339 

01310 

Advanced Beneficiary Notice Code 

21 

250 

XON 

O 

Y 

 

01311

Ordering Facility Name 

22 

250

XAD 

O 

Y 

 

01312 

Ordering Facility Address 

23 

250 

XTN 

O 

Y 

 

01313 

Ordering Facility Phone Number

24 

250 

XAD 

O 

Y 

 

01314 

Ordering Provider Address 

25 

250

CWE 

O 

N 

 

01473 

Order Status Modifier 

ORC use notes:

* ALERT: Variance with HL7 2.4 International. 

** ALERT: The field length of ORC-2, ORC-3 and ORC-4 of 250 characters for Australian usage is a variance to the HL7 V 2.4 field length of 22 characters.

a) placer order groups

The Standard supports a mechanism to collect several orders together in a group. Most often this is used to represent an “ordering session” for a single patient.

An order group is a list of orders (ORCs) associated with an ORC-4-placer group number. A group is established when the placer supplies a placer group number with the original order. The order group consists of all the ORCs and order detail segments that have the same placer group number. Orders can be removed from the group using cancel, or added using the replacement or parent-child mechanisms.

New orders cannot otherwise be added to the group.

b) duplicate fields

The ORC is intended to uniformly define the fields that are common to all orders (i.e., requested services). Some ORC fields are duplicated in some order detail segments (e.g., OBR, RXO). For example, ORC-2-placer order number has the same meaning and purpose as OBR-2-placer order number field. This promotes upward compatibility with past versions and ASTM.

The rule for using these fields is that the value must appear in the order detail segment if it does not appear in the ORC. However, it is recommended to transmit the field value in both places to avoid confusion.

c) parent/child - cancel, hold, discontinue

During transmission of a request to cancel, hold, or discontinue a parent order, the request is intended to apply recursively to the parent order and all associated child orders.

For example:

1) An ECG application receives an order for three ECGs on successive mornings.

2) The ECG application creates three child orders, one for each requested ECG.

3) The first daily ECG has already been performed when a request is received to cancel the original parent order. (The parent is beyond the point of cancellation.)

4) The remaining, unperformed, children are cancelled as a result of the request.