DSTU2 QA Preview

This page is part of the FHIR Specification (v1.0.0: DSTU 2 Ballot 3). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions

4.22 Resource DiagnosticOrder - Content

Orders and Observations Work GroupMaturity Level: 1Compartments: Device, Encounter, Patient, Practitioner

A record of a request for a diagnostic investigation service to be performed.

4.22.1 Scope and Usage

A Diagnostic Order is a record of a request for a set of diagnostic investigations to be performed. The investigation will lead to a Diagnostic Report that summarizes the outcome of the investigation, and includes any useful data and/or images that are relevant to the treatment/management of the subject.

The principal intention of the Diagnostic Order is to support ordering diagnostic investigations on patients (which includes non-human patients in veterinary medicine). However in many contexts, healthcare related processes include performing diagnostic investigations on groups of subjects, devices involved in the provision of healthcare, and even environmental locations such as ducts, bodies of water, etc. The Diagnostic Order supports all these usages.

The general work flow that this resource facilitates is that a clinical system creates a diagnostic order. The diagnostic order is then exchanged, perhaps via intermediaries, with a system that represents a diagnostic service that can perform the investigation as a request to do so. The diagnostic service will update the request as the work is performed, and then finally issue a report that references the requests that it fulfills.

4.22.2 Boundaries and Relationships

DiagnosticOrder is closely related to other types of "request" resources, particularly ReferralRequest and ProcedureRequest. In fact, for some services, it may be appropriate to use any one of these resources to request that the service be performed. Which one is used may be driven by organization practice and by context. When it is unclear which to use, the following principles may be helpful:

  • ProcedureRequest or DiagnosticOrder are typically used when the requesting clinician has and wishes to exercise the authority (and expertise) to decide exactly what action will be done.
  • A ReferralRequest is used when the requesting practitioner is seeking another practitioner or organization to use their own expertise and/or authority to determine the specific action to take.
  • Whether an activity is deemed to be a procedure or only a diagnostic order is typically driven by how invasive the diagnostic process is. More invasive processes are typically represented as procedures, though the dividing line will vary by organization.
Irrespective of the guidance above, systems should be prepared for some degree of overlap between these resources and be prepared to execute searches against multiple resources in cases where differentiation cannot be guaranteed. As well, in some workflows more than one type of resource or even all three might exist. E.g. Upon receiving a ReferralRequest a practitioner might initiate a DiagnosticOrder. The diagnostic service might then initiate a ProcedureRequest.

The DiagnosticOrder supports references to the numerous other resources that define information about the subject, the orderer, associated encounter, specimen the bodysite and other supporting information. For example, Patient, Practitioner Specimen and Condition are all referenced in this resource. While some systems may choose to bundle up a DiagnosticOrder and this referenced information into a Document for delivery to the recipient. However, REST, Messaging and Services are also valid architectures for managing referrals and may be more appropriate where active workflow management is needed.

The CarePlan resource can be used to describe more sophisticated requests for combinations of services and DiagnosticOrder may be referenced as part of a CarePlan. Similarily ClinicalImpression resource can ireference DiagnosticOrder as part of a followup to plan to the assessment.

Note that the Diagnostic Order itself is not a request to perform the investigation - but rather a record of the fact that a request was made. To actually initiate the workflow beyond simply the existence of a Diagnostic Order may be required. This can be achieved by using an Order resource, with the Diagnostic Order referenced from the Order.details, or by using the Diagnostic Order resource in the context of an messaging or service workflow where the request is explicit or implicit."

This resource is referenced by CarePlan, ClinicalImpression, DiagnosticReport, ImagingStudy and Procedure

4.22.3 Resource Content

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. DiagnosticOrder DomainResourceA request for a diagnostic service
... subject Σ1..1Reference(Patient | Group | Location | Device)Who and/or what test is about
... orderer Σ0..1Reference(Practitioner)Who ordered the test
... identifier Σ0..*IdentifierIdentifiers assigned to this order
... encounter Σ0..1Reference(Encounter)The encounter that this diagnostic order is associated with
... reason 0..*CodeableConceptExplanation/Justification for test
Condition/Problem/Diagnosis Codes (Example)
... supportingInformation 0..*Reference(Observation | Condition | DocumentReference)Additional clinical information
... specimen 0..*Reference(Specimen)If the whole order relates to specific specimens
... status ?! Σ0..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
... priority Σ0..1coderoutine | urgent | stat | asap
DiagnosticOrderPriority (Required)
... event 0..*BackboneElementA list of events of interest in the lifecycle
.... status Σ1..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
.... description Σ0..1CodeableConceptMore information about the event and its context
Diagnostic Order Event Codes (Example)
.... dateTime Σ1..1dateTimeThe date at which the event happened
.... actor 0..1Reference(Practitioner | Device)Who recorded or did this
... item 0..*BackboneElementThe items the orderer requested
.... code Σ1..1CodeableConceptCode to indicate the item (test or panel) being ordered
LOINC Diagnostic Order Codes (Preferred)
.... specimen 0..*Reference(Specimen)If this item relates to specific specimens
.... bodySite 0..1CodeableConceptLocation of requested test (if applicable)
SNOMED CT Body Structures (Example)
.... status Σ0..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
.... event Σ0..*see eventEvents specific to this item
... note 0..*AnnotationOther notes and comments

doco Documentation for this format

UML Diagram

DiagnosticOrder (DomainResource)Who or what the investigation is to be performed on. This is usually a human patient, but diagnostic tests can also be requested on animals, groups of humans or animals, devices such as dialysis machines, or even locations (typically for environmental scans)subject : Reference [1..1] « Patient|Group|Location|Device »The practitioner that holds legal responsibility for ordering the investigationorderer : Reference [0..1] « Practitioner »Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfilleridentifier : Identifier [0..*]An encounter that provides additional information about the healthcare context in which this request is madeencounter : Reference [0..1] « Encounter »An explanation or justification for why this diagnostic investigation is being requested. This is often for billing purposes. May relate to the resources referred to in supportingInformationreason : CodeableConcept [0..*] « Diagnosis or problem codes justifying the reason for requesting the diagnostic investigation (Strength=Example)Condition/Problem/Diagnosis ?? »Additional clinical information about the patient or specimen that may influence test interpretations. This includes observations explicitly requested by the producer(filler) to provide context or supporting information needed to complete the ordersupportingInformation : Reference [0..*] « Observation|Condition| DocumentReference »One or more specimens that the diagnostic investigation is aboutspecimen : Reference [0..*] « Specimen »The status of the order (this element modifies the meaning of other elements)status : code [0..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »The clinical priority associated with this orderpriority : code [0..1] « The clinical priority of a diagnostic order (Strength=Required)DiagnosticOrderPriority! »Any other notes associated with this patient or specimen or order (e.g. "patient hates needles")note : Annotation [0..*]EventThe status for the eventstatus : code [1..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »Additional information about the event that occurred - e.g. if the status remained unchangeddescription : CodeableConcept [0..1] « Additional information about an event that occurred to a diagnostic order - e.g. if the status remained unchanged (Strength=Example)Diagnostic Order Event ?? »The date/time at which the event occurreddateTime : dateTime [1..1]The person who was responsible for performing or recording the actionactor : Reference [0..1] « Practitioner|Device »ItemA code that identifies a particular diagnostic investigation, or panel of investigations, that have been requestedcode : CodeableConcept [1..1] « Codes for tests/services that can be performed by diagnostic services (Strength=Preferred)LOINC Diagnostic Order ? »If the item is related to a specific specimenspecimen : Reference [0..*] « Specimen »Anatomical location where the request test should be performed. This is the target sitebodySite : CodeableConcept [0..1] « Codes describing anatomical locations. May include laterality (Strength=Example)SNOMED CT Body Structures?? »The status of this individual item within the orderstatus : code [0..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »A summary of the events of interest that have occurred as the request is processed. E.g. when the order was made, various processing steps (specimens received), when it was completedevent[0..*]A summary of the events of interest that have occurred as this item of the request is processedevent[0..*]The specific diagnostic investigations that are requested as part of this request. Sometimes, there can only be one item per request, but in most contexts, more than one investigation can be requesteditem[0..*]

XML Template

<DiagnosticOrder xmlns="http://hl7.org/fhir"> doco
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <subject><!-- 1..1 Reference(Patient|Group|Location|Device) Who and/or what test is about --></subject>
 <orderer><!-- 0..1 Reference(Practitioner) Who ordered the test --></orderer>
 <identifier><!-- 0..* Identifier Identifiers assigned to this order --></identifier>
 <encounter><!-- 0..1 Reference(Encounter) The encounter that this diagnostic order is associated with --></encounter>
 <reason><!-- 0..* CodeableConcept Explanation/Justification for test --></reason>
 <supportingInformation><!-- 0..* Reference(Observation|Condition|
   DocumentReference) Additional clinical information --></supportingInformation>
 <specimen><!-- 0..* Reference(Specimen) If the whole order relates to specific specimens --></specimen>
 <status value="[code]"/><!-- 0..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
 <priority value="[code]"/><!-- 0..1 routine | urgent | stat | asap -->
 <event>  <!-- 0..* A list of events of interest in the lifecycle -->
  <status value="[code]"/><!-- 1..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
  <description><!-- 0..1 CodeableConcept More information about the event and its context --></description>
  <dateTime value="[dateTime]"/><!-- 1..1 The date at which the event happened -->
  <actor><!-- 0..1 Reference(Practitioner|Device) Who recorded or did this --></actor>
 </event>
 <item>  <!-- 0..* The items the orderer requested -->
  <code><!-- 1..1 CodeableConcept Code to indicate the item (test or panel) being ordered --></code>
  <specimen><!-- 0..* Reference(Specimen) If this item relates to specific specimens --></specimen>
  <bodySite><!-- 0..1 CodeableConcept Location of requested test (if applicable) --></bodySite>
  <status value="[code]"/><!-- 0..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
  <event><!-- 0..* Content as for DiagnosticOrder.event Events specific to this item --></event>
 </item>
 <note><!-- 0..* Annotation Other notes and comments --></note>
</DiagnosticOrder>

JSON Template

{doco
  "resourceType" : "DiagnosticOrder",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "subject" : { Reference(Patient|Group|Location|Device) }, // R!  Who and/or what test is about
  "orderer" : { Reference(Practitioner) }, // Who ordered the test
  "identifier" : [{ Identifier }], // Identifiers assigned to this order
  "encounter" : { Reference(Encounter) }, // The encounter that this diagnostic order is associated with
  "reason" : [{ CodeableConcept }], // Explanation/Justification for test
  "supportingInformation" : [{ Reference(Observation|Condition|
   DocumentReference) }], // Additional clinical information
  "specimen" : [{ Reference(Specimen) }], // If the whole order relates to specific specimens
  "status" : "<code>", // proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
  "priority" : "<code>", // routine | urgent | stat | asap
  "event" : [{ // A list of events of interest in the lifecycle
    "status" : "<code>", // R!  proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
    "description" : { CodeableConcept }, // More information about the event and its context
    "dateTime" : "<dateTime>", // R!  The date at which the event happened
    "actor" : { Reference(Practitioner|Device) } // Who recorded or did this
  }],
  "item" : [{ // The items the orderer requested
    "code" : { CodeableConcept }, // R!  Code to indicate the item (test or panel) being ordered
    "specimen" : [{ Reference(Specimen) }], // If this item relates to specific specimens
    "bodySite" : { CodeableConcept }, // Location of requested test (if applicable)
    "status" : "<code>", // proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
    "event" : [{ Content as for DiagnosticOrder.event }] // Events specific to this item
  }],
  "note" : [{ Annotation }] // Other notes and comments
}

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. DiagnosticOrder DomainResourceA request for a diagnostic service
... subject Σ1..1Reference(Patient | Group | Location | Device)Who and/or what test is about
... orderer Σ0..1Reference(Practitioner)Who ordered the test
... identifier Σ0..*IdentifierIdentifiers assigned to this order
... encounter Σ0..1Reference(Encounter)The encounter that this diagnostic order is associated with
... reason 0..*CodeableConceptExplanation/Justification for test
Condition/Problem/Diagnosis Codes (Example)
... supportingInformation 0..*Reference(Observation | Condition | DocumentReference)Additional clinical information
... specimen 0..*Reference(Specimen)If the whole order relates to specific specimens
... status ?! Σ0..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
... priority Σ0..1coderoutine | urgent | stat | asap
DiagnosticOrderPriority (Required)
... event 0..*BackboneElementA list of events of interest in the lifecycle
.... status Σ1..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
.... description Σ0..1CodeableConceptMore information about the event and its context
Diagnostic Order Event Codes (Example)
.... dateTime Σ1..1dateTimeThe date at which the event happened
.... actor 0..1Reference(Practitioner | Device)Who recorded or did this
... item 0..*BackboneElementThe items the orderer requested
.... code Σ1..1CodeableConceptCode to indicate the item (test or panel) being ordered
LOINC Diagnostic Order Codes (Preferred)
.... specimen 0..*Reference(Specimen)If this item relates to specific specimens
.... bodySite 0..1CodeableConceptLocation of requested test (if applicable)
SNOMED CT Body Structures (Example)
.... status Σ0..1codeproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
DiagnosticOrderStatus (Required)
.... event Σ0..*see eventEvents specific to this item
... note 0..*AnnotationOther notes and comments

doco Documentation for this format

UML Diagram

DiagnosticOrder (DomainResource)Who or what the investigation is to be performed on. This is usually a human patient, but diagnostic tests can also be requested on animals, groups of humans or animals, devices such as dialysis machines, or even locations (typically for environmental scans)subject : Reference [1..1] « Patient|Group|Location|Device »The practitioner that holds legal responsibility for ordering the investigationorderer : Reference [0..1] « Practitioner »Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfilleridentifier : Identifier [0..*]An encounter that provides additional information about the healthcare context in which this request is madeencounter : Reference [0..1] « Encounter »An explanation or justification for why this diagnostic investigation is being requested. This is often for billing purposes. May relate to the resources referred to in supportingInformationreason : CodeableConcept [0..*] « Diagnosis or problem codes justifying the reason for requesting the diagnostic investigation (Strength=Example)Condition/Problem/Diagnosis ?? »Additional clinical information about the patient or specimen that may influence test interpretations. This includes observations explicitly requested by the producer(filler) to provide context or supporting information needed to complete the ordersupportingInformation : Reference [0..*] « Observation|Condition| DocumentReference »One or more specimens that the diagnostic investigation is aboutspecimen : Reference [0..*] « Specimen »The status of the order (this element modifies the meaning of other elements)status : code [0..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »The clinical priority associated with this orderpriority : code [0..1] « The clinical priority of a diagnostic order (Strength=Required)DiagnosticOrderPriority! »Any other notes associated with this patient or specimen or order (e.g. "patient hates needles")note : Annotation [0..*]EventThe status for the eventstatus : code [1..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »Additional information about the event that occurred - e.g. if the status remained unchangeddescription : CodeableConcept [0..1] « Additional information about an event that occurred to a diagnostic order - e.g. if the status remained unchanged (Strength=Example)Diagnostic Order Event ?? »The date/time at which the event occurreddateTime : dateTime [1..1]The person who was responsible for performing or recording the actionactor : Reference [0..1] « Practitioner|Device »ItemA code that identifies a particular diagnostic investigation, or panel of investigations, that have been requestedcode : CodeableConcept [1..1] « Codes for tests/services that can be performed by diagnostic services (Strength=Preferred)LOINC Diagnostic Order ? »If the item is related to a specific specimenspecimen : Reference [0..*] « Specimen »Anatomical location where the request test should be performed. This is the target sitebodySite : CodeableConcept [0..1] « Codes describing anatomical locations. May include laterality (Strength=Example)SNOMED CT Body Structures?? »The status of this individual item within the orderstatus : code [0..1] « The status of a diagnostic order (Strength=Required)DiagnosticOrderStatus! »A summary of the events of interest that have occurred as the request is processed. E.g. when the order was made, various processing steps (specimens received), when it was completedevent[0..*]A summary of the events of interest that have occurred as this item of the request is processedevent[0..*]The specific diagnostic investigations that are requested as part of this request. Sometimes, there can only be one item per request, but in most contexts, more than one investigation can be requesteditem[0..*]

XML Template

<DiagnosticOrder xmlns="http://hl7.org/fhir"> doco
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <subject><!-- 1..1 Reference(Patient|Group|Location|Device) Who and/or what test is about --></subject>
 <orderer><!-- 0..1 Reference(Practitioner) Who ordered the test --></orderer>
 <identifier><!-- 0..* Identifier Identifiers assigned to this order --></identifier>
 <encounter><!-- 0..1 Reference(Encounter) The encounter that this diagnostic order is associated with --></encounter>
 <reason><!-- 0..* CodeableConcept Explanation/Justification for test --></reason>
 <supportingInformation><!-- 0..* Reference(Observation|Condition|
   DocumentReference) Additional clinical information --></supportingInformation>
 <specimen><!-- 0..* Reference(Specimen) If the whole order relates to specific specimens --></specimen>
 <status value="[code]"/><!-- 0..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
 <priority value="[code]"/><!-- 0..1 routine | urgent | stat | asap -->
 <event>  <!-- 0..* A list of events of interest in the lifecycle -->
  <status value="[code]"/><!-- 1..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
  <description><!-- 0..1 CodeableConcept More information about the event and its context --></description>
  <dateTime value="[dateTime]"/><!-- 1..1 The date at which the event happened -->
  <actor><!-- 0..1 Reference(Practitioner|Device) Who recorded or did this --></actor>
 </event>
 <item>  <!-- 0..* The items the orderer requested -->
  <code><!-- 1..1 CodeableConcept Code to indicate the item (test or panel) being ordered --></code>
  <specimen><!-- 0..* Reference(Specimen) If this item relates to specific specimens --></specimen>
  <bodySite><!-- 0..1 CodeableConcept Location of requested test (if applicable) --></bodySite>
  <status value="[code]"/><!-- 0..1 proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed -->
  <event><!-- 0..* Content as for DiagnosticOrder.event Events specific to this item --></event>
 </item>
 <note><!-- 0..* Annotation Other notes and comments --></note>
</DiagnosticOrder>

JSON Template

{doco
  "resourceType" : "DiagnosticOrder",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "subject" : { Reference(Patient|Group|Location|Device) }, // R!  Who and/or what test is about
  "orderer" : { Reference(Practitioner) }, // Who ordered the test
  "identifier" : [{ Identifier }], // Identifiers assigned to this order
  "encounter" : { Reference(Encounter) }, // The encounter that this diagnostic order is associated with
  "reason" : [{ CodeableConcept }], // Explanation/Justification for test
  "supportingInformation" : [{ Reference(Observation|Condition|
   DocumentReference) }], // Additional clinical information
  "specimen" : [{ Reference(Specimen) }], // If the whole order relates to specific specimens
  "status" : "<code>", // proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
  "priority" : "<code>", // routine | urgent | stat | asap
  "event" : [{ // A list of events of interest in the lifecycle
    "status" : "<code>", // R!  proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
    "description" : { CodeableConcept }, // More information about the event and its context
    "dateTime" : "<dateTime>", // R!  The date at which the event happened
    "actor" : { Reference(Practitioner|Device) } // Who recorded or did this
  }],
  "item" : [{ // The items the orderer requested
    "code" : { CodeableConcept }, // R!  Code to indicate the item (test or panel) being ordered
    "specimen" : [{ Reference(Specimen) }], // If this item relates to specific specimens
    "bodySite" : { CodeableConcept }, // Location of requested test (if applicable)
    "status" : "<code>", // proposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failed
    "event" : [{ Content as for DiagnosticOrder.event }] // Events specific to this item
  }],
  "note" : [{ Annotation }] // Other notes and comments
}

 

Alternate definitions: Schema/Schematron, Resource Profile (XML, JSON), Questionnaire

4.22.3.1 Terminology Bindings

PathDefinitionTypeReference
DiagnosticOrder.reason Diagnosis or problem codes justifying the reason for requesting the diagnostic investigationExampleCondition/Problem/Diagnosis Codes
DiagnosticOrder.status
DiagnosticOrder.event.status
DiagnosticOrder.item.status 		The status of a diagnostic orderRequiredDiagnosticOrderStatus
DiagnosticOrder.priority The clinical priority of a diagnostic orderRequiredDiagnosticOrderPriority
DiagnosticOrder.event.description Additional information about an event that occurred to a diagnostic order - e.g. if the status remained unchangedExampleDiagnostic Order Event Codes
DiagnosticOrder.item.code Codes for tests/services that can be performed by diagnostic servicesPreferredLOINC Diagnostic Order Codes
DiagnosticOrder.item.bodySite Codes describing anatomical locations. May include lateralityExampleSNOMED CT Body Structures

4.22.4 Notes:

  • In normal practice, there would always be at least one item in a request (no point requesting nothing), but the minimum cardinality is 0 so that a workflow can quote order details (identifiers, requester) without having to list the items
  • Typically the system placing the order sets the status to requested. There after, the order is maintained by the receiver that updates the status as the request is processed
  • If the request has multiple items that have their own life cycles, then the items will have their own status while the overall diagnostic order is (usually) "in-progress"
  • The event list is not the same as an audit trail - it is a view of the important things that happened in the past. Typically, there would only be one entry for any given status, and systems may not record all the status events
  • Many investigation requests will create a need for specimens, but in these cases, the request itself is not actually about the specimens. This specimen elements in this resource are provided for when the diagnostic investigation is requested on already existing specimens
  • A single specimen should not appear in both DiagnosticOrder.specimen and DiagnosticOrder.item.specimen - DiagnosticOrder.specimen should only be used when the entire order relates to a single specimen, and then there is no need to repeat it for each item
  • The reason is often for billing purposes. May relate to the resources referred to in supportingInformation and used to decide how the diagnostic investigation will be performed, or even if it will be performed at all
  • The identifier.type element is used to distinguish between the identifiers assigned by the orderer (known as the 'Placer' in HL7 v2 ) and the producer of the observations in response to the order ( known the 'Filler' in HL7 v2) . Use the identfier type code "PLAC" for the Placer Identifier and "FILL" for the Filler identifier. See the example code below: 
    
<!-- Placer identifier-->
  <identifier>
		<type>
			<coding>
				<system value="http://hl7.org/fhir/identifier-type"/>
				<code value="PLAC"/>
			</coding>
			<text value="Placer"/>
		</type>
		<system value="urn:oid:1.3.4.5.6.7"/>
		<value value="2345234234234"/>
	</identifier>
<!-- Filler identifier-->
  <identifier>
		<type>
			<coding>
				<system value="http://hl7.org/fhir/identifier-type"/>
				<code value="PLAC"/>
			</coding>
			<text value="Placer"/>
		</type>
	<system value=" http://hl7.org/fhir/identifier-type"/>
	<value value="567890"/>
  </identifier>

4.22.5 Search Parameters

Search parameters for this resource. The common parameters also apply. See Searching for more information about searching in REST, messaging, and services.

NameTypeDescriptionPaths
actorreferenceWho recorded or did thisDiagnosticOrder.event.actor, DiagnosticOrder.item.event.actor
(Device, Practitioner)
bodysitetokenLocation of requested test (if applicable)DiagnosticOrder.item.bodySite
codetokenCode to indicate the item (test or panel) being orderedDiagnosticOrder.item.code
encounterreferenceThe encounter that this diagnostic order is associated withDiagnosticOrder.encounter
(Encounter)
event-datedateThe date at which the event happenedDiagnosticOrder.event.dateTime
event-statustokenproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failedDiagnosticOrder.event.status
event-status-datecompositeA combination of past-status and date
identifiertokenIdentifiers assigned to this orderDiagnosticOrder.identifier
item-datedateThe date at which the event happenedDiagnosticOrder.item.event.dateTime
item-past-statustokenproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failedDiagnosticOrder.item.event.status
item-statustokenproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failedDiagnosticOrder.item.status
item-status-datecompositeA combination of item-past-status and item-date
ordererreferenceWho ordered the testDiagnosticOrder.orderer
(Practitioner)
patientreferenceWho and/or what test is aboutDiagnosticOrder.subject
(Patient)
specimenreferenceIf the whole order relates to specific specimensDiagnosticOrder.specimen, DiagnosticOrder.item.specimen
(Specimen)
statustokenproposed | draft | planned | requested | received | accepted | in-progress | review | completed | cancelled | suspended | rejected | failedDiagnosticOrder.status
subjectreferenceWho and/or what test is aboutDiagnosticOrder.subject
(Device, Location, Patient, Group)