# US Core Observation Clinical Result Profile - US Core Implementation Guide v9.0.0

* [**Table of Contents**](toc.md)
* [**Artifacts Summary**](artifacts.md)
* **US Core Observation Clinical Result Profile**

## Resource Profile: US Core Observation Clinical Result Profile 

| | | |
| :--- | :--- | :--- |
| *Official URL*:http://hl7.org/fhir/us/core/StructureDefinition/us-core-observation-clinical-result | *Version*:9.0.0 | |
| * Standards status: *[Trial-use](http://hl7.org/fhir/R4/versions.html#std-process) | [Maturity Level](changes-between-versions.md#us-core-maturity-levels): 4 | *Computable Name*:USCoreObservationClinicalResultProfile |
| *Other Identifiers:*OID:2.16.840.1.113883.4.642.40.2.42.42 | | |

 
The US Core Observation Clinical Result Profile is based upon the core FHIR Observation Resource and, along with the US Core DiagnosticReport Profile, meets the US Core Data for Interoperability (USCDI) requirements for **Diagnostic Imaging** and **Clinical Tests** Data Classes. This profile sets minimum expectations for the Observation resource to record and search non-laboratory clinical test results (e.g., radiology and other clinical observations generated from procedures). An example would be when a gastroenterologist reports the size of a polyp observed during a colonoscopy. This profile is the basis for the US Core Laboratory Result Observation Profile, which defines additional data elements to record and search laboratory test results. 
The US Core Observation Clinical Result Profile sets minimum expectations to promote interoperability and adoption through common implementation. It identifies which core elements, extensions, vocabularies, and value sets **SHALL** be present in the resource and constrains the way the elements are used when using this profile. It provides the floor for standards development for specific use cases. 

**Example Usage Scenarios:**

The following are example usage scenarios for this profile:

* Query for clinical tests or diagnostic imaging results for a patient.
* [Record or update](us-core-roadmap.md#future-candidate-requirements-under-consideration) clinical tests or diagnostic imaging results belonging to a Patient

### Mandatory and Must Support Data Elements

The following data elements must always be present ([Mandatory](must-support.md) definition) or must be supported if the data is present in the sending system ([Must Support](must-support.md) definition). They are presented below in a simple human-readable explanation. Profile-specific guidance and examples are provided as well. The [Formal Views](#profile) below provides the formal summary, definitions, and terminology requirements.

**Each Observation Must Have:**

1. a status
1. a category code
1. a[LOINC](http://loinc.org)code, if available, which tells you what is being measured
1. a patient

**Each Observation Must Support:**

1. encounter associated with Observation
1. a time indicating when the measurement was taken
1. a performer2
1. a result value
* if the result value is a numeric quantity, a standard [UCUM](http://unitsofmeasure.org) unit

1. a reason why the data is absent1

1,2 see guidance below

### Profile Specific Implementation Guidance

This section provides detailed implementation guidance for the US Core Profile to support implementation and certification.

* See the [US Core Laboratory Result Observation Profile](StructureDefinition-us-core-observation-lab.md) to represent laboratory test results.

* Servers **SHOULD** use the base FHIR [Observation Category Codes](http://hl7.org/fhir/R4/valueset-observation-category.html).[§](requirements.md#CONF-0423) The `Observation.category` element provides an efficient way of restricting search on observations to a given context such as procedure, exam or laboratory observations. Example searches are shown in the [Quick Start](#search) section below. However, Clients need to understand that data categorization is somewhat subjective. The categorization applied by the source may not align with the Client's expectations. Clients may find it more useful to use queries based on a specific code or set of codes or to perform additional Client-side filtering of query results.
* A code system value **SHOULD** be supplied for each additional code.[§](requirements.md#CONF-0420)
* Systems **SHOULD** support `Observation.effectivePeriod` to accurately represent measurements over time .[§](requirements.md#CONF-0424)
* 1An Observation without a value, **SHALL** include a reason why the data is absent **unless** there are 1) component observations, or 2) reporting panel observations using `Observation.hasMember`.[§](requirements.md#CONF-0427),[§](requirements.md#CONF-0428) 
* For further guidance, see the [Observation Grouping](http://hl7.org/fhir/R4/observation.html#obsgrouping) section in FHIR Specification.
* Systems that never provide an observation without a value **MAY** choose not to support `Observation.dataAbsentReason`.[§](requirements.md#CONF-0429)
 
* 1An `Observation.component` without a value, **SHALL** include a reason why the data is absent.[§](requirements.md#CONF-0425) 
* Systems that never provide a component observation without a component value **MAY** choose not to support `Observation.component.dataAbsentReason`.[§](requirements.md#CONF-0426)
 
* See the [General Guidance](general-guidance.md) page for further guidance on SNOMED and UCUM.
* See the [LOINC scale type to FHIR data type mapping](http://hl7.org/fhir/R4/loinc.html#dataelements) for guidance on which `Observation.value[x]` data type to use based on the LOINC Type of Scale.

* For a **starter set** of example clinical test LOINC codes, see [Appendix B in U.S. Core Data for Interoperability (USCDI) Task Force 2021 HITAC Phase 3 Recommendations Report Letter](https://www.healthit.gov/sites/default/files/page/2021-10/2021-09-09_USCDI_TF_2021_HITAC_Phase%203_%20Recommendations%20Report_Signed_508.pdf).

* 2The profile elements `Observation.performer and Observation.device` communicate the [individual level provenance](basic-provenance.md#individual-level-provenance) author data corresponding to the U.S. Core Data for Interoperability (USCDI) Provenance Author Data Elements.

**Usages:**

* Derived from this Profile: [US Core Laboratory Result Observation Profile](StructureDefinition-us-core-observation-lab.md)
* Refer to this Profile: [US Core DiagnosticReport Profile for Report and Note Exchange](StructureDefinition-us-core-diagnosticreport-note.md)
* Examples for this Profile: [Observation/capillary-refill-time-nail-bed](Observation-capillary-refill-time-nail-bed.md), [Observation/dxa-femur-l-armass-bmd](Observation-dxa-femur-l-armass-bmd.md), [Observation/dxa-femur-l-t-score-bmd](Observation-dxa-femur-l-t-score-bmd.md), [Observation/dxa-femur-l-z-score-bmd](Observation-dxa-femur-l-z-score-bmd.md)... Show 13 more, [Observation/dxa-hip-l-armass-bmd](Observation-dxa-hip-l-armass-bmd.md), [Observation/dxa-hip-l-t-score-bmd](Observation-dxa-hip-l-t-score-bmd.md), [Observation/dxa-hip-l-z-score-bmd](Observation-dxa-hip-l-z-score-bmd.md), [Observation/ekg-impression](Observation-ekg-impression.md), [Observation/ekg-lead](Observation-ekg-lead.md), [Observation/heart-rate-rhythm](Observation-heart-rate-rhythm.md), [Observation/jugular-vein-distension](Observation-jugular-vein-distension.md), [Observation/p-r-interval-ekg-lead](Observation-p-r-interval-ekg-lead.md), [Observation/pulse-intensity-palpation](Observation-pulse-intensity-palpation.md), [Observation/q-t-interval-ekg-lead](Observation-q-t-interval-ekg-lead.md), [Observation/qrs-dur-ekg-lead](Observation-qrs-dur-ekg-lead.md), [Observation/xray-chest-findings](Observation-xray-chest-findings.md) and [Observation/xray-chest-impression](Observation-xray-chest-impression.md)
* CapabilityStatements using this Profile: [US Core Client CapabilityStatement](CapabilityStatement-us-core-client.md) and [US Core Server CapabilityStatement](CapabilityStatement-us-core-server.md)

You can also check for [usages in the FHIR IG Statistics](https://packages2.fhir.org/xig/hl7.fhir.us.core|current/StructureDefinition/us-core-observation-clinical-result)

**Changes since version 8.0.1:**

* The resource metadata has changed (copyright)

* One or more text definitions, invariants or bindings have changed

### Formal Views of Profile Content

 [Description of Profiles, Differentials, Snapshots and how the different presentations work](http://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#structure-definitions). 

 

Other representations of profile: [CSV](StructureDefinition-us-core-observation-clinical-result.csv), [Excel](StructureDefinition-us-core-observation-clinical-result.xlsx), [Schematron](StructureDefinition-us-core-observation-clinical-result.sch) 

### Notes:

-------

**Quick Start**  

-------

Below is an overview of the required Server RESTful FHIR interactions for this profile - for example, search and read operations - when supporting the US Core interactions to access this profile's information (Profile Support + Interaction Support). Note that systems that support only US Core Profiles (Profile Only Support) are not required to support these interactions. See the [US Core Server CapabilityStatement](CapabilityStatement-us-core-server.md) for a complete list of supported RESTful interactions for this IG.

* See the [Scopes Format](scopes.md#scopes-format) section for a description of the SMART scopes syntax.
* See the [Search Syntax](general-guidance.md#search-syntax) section for a description of the US Core search syntax.
* See the [General Requirements](general-requirements.md) section for additional rules and expectations when a Server requires status parameters.
* See the [General Guidance](general-guidance.md) section for additional guidance on searching for multiple patients.

#### US Core Scopes

Servers providing access to clinical results data **SHALL** support these [US Core SMART Scopes](scopes.md#smart-scopes):

* [resource level scopes](http://hl7.org/fhir/smart-app-launch/STU2.2/scopes-and-launch-context.html#scopes-for-requesting-clinical-data): `<patient|user|system>/Observation.rs` [§](requirements.md#CONF-0145)

-------

#### Mandatory Search Parameters:

The following search parameters and search parameter combinations **SHALL** be supported:

1. **SHALL** support searching for all Observations using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [category](SearchParameter-us-core-observation-category.md) search parameters`GET [base]/Observation?patient={Patient/}[id]&category={system|}[search_code]`Example:
> 
1. GET [base]/Observation?patient=Patient/1137192&category=http://terminology.hl7.org/CodeSystem/observation-category|procedure

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and a category code = "procedure" ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token)).
1. **SHALL** support searching for all Observations by code using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [code](SearchParameter-us-core-observation-code.md) search parameters
* Including optional support **OR** search on `code` (e.g.`code={system|}[code],{system|}[code],...`)
`GET [base]/Observation?patient={Patient/}[id]&code={system|}[search_code]{,{system|}[code],...}`Examples:
> 
1. GET [base]/Observation?patient=Patient/1137192&code=http://loinc.org|44974-4
1. GET [base]/Observation?patient=Patient/1137192&code=http://loinc.org|44974-4,http://loinc.org|44963-7,http://loinc.org|8601-7

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and observation code(s). SHOULD support search by multiple codes. The US Core Observation Clinical Result Profile "code" parameter searches only `.code` and not `component.code`. ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token)).
1. **SHALL** support searching for all Observations by date (for example, results after 2018) using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [category](SearchParameter-us-core-observation-category.md) and [date](SearchParameter-us-core-observation-date.md) search parameters
* Including optional support for **AND** search on `date` (e.g.`date=[date]&date=[date]&...`)
* Including support for these `date` comparators: "gt", "lt", "ge", "le"
`GET [base]/Observation?patient={Patient/}[id]&category={system|}[search_code]&date={gt|lt|ge|le}[dateTime]{&date={gt|lt|ge|le}[dateTime]&...}`Example:
> 
1. GET [base]/Observation?patient=Patient/1137192&category=http://terminology.hl7.org/CodeSystem/observation-category|procedure&date=ge2018-03-14T00:00:00Z

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and date and a category code = "procedure" ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token) and [how to search by date](http://hl7.org/fhir/R4/search.html#date)).

#### Optional Search Parameters:

The following search parameters and search parameter combinations **SHOULD** be supported

1. **SHOULD** support searching for all Observations for a patient for a given status (for example all observations marked as final) using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [category](SearchParameter-us-core-observation-category.md) and [status](SearchParameter-us-core-observation-status.md) search parameters
* Including support **OR** search on `status` (e.g.`status={system|}[code],{system|}[code],...`)
`GET [base]/Observation?patient={Patient/}[id]&category={system|}[search_code]&status={system|}[search_code]{,{system|}[code],...}`Example:
> 
1. GET [base]/Observation?patient=Patient/1137192&category=http://terminology.hl7.org/CodeSystem/observation-category|procedure&status=final

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and category = "procedure" and status ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token)).
1. **SHOULD** support searching using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [category](SearchParameter-us-core-observation-category.md) and [_lastUpdated](SearchParameter-us-core-observation-lastupdated.md) search parameters
* Including optional support for **AND** search on `_lastUpdated` (e.g.`_lastUpdated=[date]&_lastUpdated=[date]&...`)
* Including support for these `_lastUpdated` comparators: "gt", "lt", "ge", "le"
`GET [base]/Observation?patient={Patient/}[id]&category={system|}[search_code]&_lastUpdated=[dateTime]`Example:
> 
1. GET [base]/Observation?patient=Patient/1137192&category=http://terminology.hl7.org/CodeSystem/observation-category|procedure&_lastUpdated=ge2024-01-01T00:00:00Z

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and category code = "procedure" and _lastUpdated. See the US Core General Guidance page for [Searching Using lastUpdated](general-guidance.md#searching-using-lastupdated). ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token) and [how to search by date](http://hl7.org/fhir/R4/search.html#date)).
1. **SHOULD** support searching Observations by code and date using the combination of the [patient](SearchParameter-us-core-observation-patient.md) and [code](SearchParameter-us-core-observation-code.md) and [date](SearchParameter-us-core-observation-date.md) search parameters
* Including optional support **OR** search on `code` (e.g.`code={system|}[code],{system|}[code],...`)
* Including optional support for **AND** search on `date` (e.g.`date=[date]&date=[date]&...`)
* Including support for these `date` comparators: "gt", "lt", "ge", "le"
`GET [base]/Observation?patient={Patient/}[id]&code={system|}[search_code]{,{system|}[code],...}&date={gt|lt|ge|le}[dateTime]{&date={gt|lt|ge|le}[dateTime]&...}`Example:
> 
1. GET [base]/Observation?patient=Patient/1137192&code=http://loinc.org|44974-4&date=ge2019-01-01T00:00:00Z

**Implementation Notes**: Fetches a bundle of all US Core Observation Clinical Result Profile resources for the specified patient and date and code(s). SHOULD support search by multiple codes. ( see [how to search by reference](http://hl7.org/fhir/R4/search.html#reference) and [how to search by token](http://hl7.org/fhir/R4/search.html#token) and [how to search by date](http://hl7.org/fhir/R4/search.html#date)).



## Resource Content

```json
{
  "resourceType" : "StructureDefinition",
  "id" : "us-core-observation-clinical-result",
  "extension" : [{
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
    "valueInteger" : 4
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
    "valueCode" : "cgp"
  },
  {
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
    "valueCode" : "trial-use",
    "_valueCode" : {
      "extension" : [{
        "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
        "valueCanonical" : "http://hl7.org/fhir/us/core/ImplementationGuide/hl7.fhir.us.core"
      }]
    }
  }],
  "url" : "http://hl7.org/fhir/us/core/StructureDefinition/us-core-observation-clinical-result",
  "identifier" : [{
    "system" : "urn:ietf:rfc:3986",
    "value" : "urn:oid:2.16.840.1.113883.4.642.40.2.42.42"
  }],
  "version" : "9.0.0",
  "name" : "USCoreObservationClinicalResultProfile",
  "title" : "US Core Observation Clinical Result Profile",
  "status" : "active",
  "date" : "2023-10-17",
  "publisher" : "HL7 International / Cross-Group Projects",
  "contact" : [{
    "name" : "HL7 International / Cross-Group Projects",
    "telecom" : [{
      "system" : "url",
      "value" : "http://www.hl7.org/Special/committees/cgp"
    },
    {
      "system" : "email",
      "value" : "cgp@lists.HL7.org"
    }]
  }],
  "description" : "The US Core Observation Clinical Result Profile is based upon the core FHIR Observation Resource and, along with the US Core DiagnosticReport Profile, meets the US Core Data for Interoperability (USCDI) requirements for *Diagnostic Imaging* and *Clinical Tests* Data Classes. This profile sets minimum expectations for the Observation resource to record and search non-laboratory clinical test results (e.g., radiology and other clinical observations generated from procedures). An example would be when a gastroenterologist reports the size of a polyp observed during a colonoscopy. This profile is the basis for the US Core Laboratory Result Observation Profile, which defines additional data elements to record and search laboratory test results.\n\nThe US Core Observation Clinical Result Profile sets minimum expectations to promote interoperability and adoption through common implementation. It identifies which core elements, extensions, vocabularies, and value sets **SHALL** be present in the resource and constrains the way the elements are used when using this profile. It provides the floor for standards development for specific use cases.",
  "jurisdiction" : [{
    "coding" : [{
      "system" : "urn:iso:std:iso:3166",
      "code" : "US"
    }]
  }],
  "fhirVersion" : "4.0.1",
  "mapping" : [{
    "identity" : "workflow",
    "uri" : "http://hl7.org/fhir/workflow",
    "name" : "Workflow Pattern"
  },
  {
    "identity" : "sct-concept",
    "uri" : "http://snomed.info/conceptdomain",
    "name" : "SNOMED CT Concept Domain Binding"
  },
  {
    "identity" : "v2",
    "uri" : "http://hl7.org/v2",
    "name" : "HL7 v2 Mapping"
  },
  {
    "identity" : "rim",
    "uri" : "http://hl7.org/v3",
    "name" : "RIM Mapping"
  },
  {
    "identity" : "w5",
    "uri" : "http://hl7.org/fhir/fivews",
    "name" : "FiveWs Pattern Mapping"
  },
  {
    "identity" : "sct-attr",
    "uri" : "http://snomed.org/attributebinding",
    "name" : "SNOMED CT Attribute Binding"
  }],
  "kind" : "resource",
  "abstract" : false,
  "type" : "Observation",
  "baseDefinition" : "http://hl7.org/fhir/StructureDefinition/Observation",
  "derivation" : "constraint",
  "differential" : {
    "element" : [{
      "id" : "Observation",
      "path" : "Observation",
      "constraint" : [{
        "key" : "us-core-2",
        "severity" : "error",
        "human" : "If there is no component or hasMember element then either a value[x] or a data absent reason must be present",
        "expression" : "(component.empty() and hasMember.empty()) implies (dataAbsentReason.exists() or value.exists())",
        "xpath" : "exists(f:component) or exists(f:hasMember) or exists(f:*[starts-with(local-name(.), 'value')]) or exists(f:dataAbsentReason)"
      }],
      "mustSupport" : false
    },
    {
      "id" : "Observation.status",
      "path" : "Observation.status",
      "mustSupport" : true
    },
    {
      "id" : "Observation.category",
      "path" : "Observation.category",
      "slicing" : {
        "discriminator" : [{
          "type" : "value",
          "path" : "$this"
        }],
        "rules" : "open"
      },
      "min" : 1,
      "mustSupport" : true
    },
    {
      "id" : "Observation.category:us-core",
      "path" : "Observation.category",
      "sliceName" : "us-core",
      "short" : "Classification of type of observation",
      "mustSupport" : true,
      "binding" : {
        "strength" : "required",
        "description" : "Note that other codes are permitted in other slices, see [Required Bindings When Slicing by Value Sets](general-requirements.html#required-bindings-when-slicing-by-valuesets)",
        "valueSet" : "http://hl7.org/fhir/us/core/ValueSet/us-core-clinical-result-observation-category"
      }
    },
    {
      "id" : "Observation.code",
      "path" : "Observation.code",
      "short" : "Clinical Test or Procedure Name",
      "definition" : "The name of the clinical test or procedure performed on a patient.  A LOINC **SHALL** be used if the concept is present in LOINC.",
      "comment" : "The typical patterns for codes are:  1)  a LOINC code either as a translation from a \"local\" code or as a primary code, or 2)  a local code only if no suitable LOINC exists,  or 3)  both the local and the LOINC translation.   Systems SHALL be capable of sending the local code if one exists.  When using LOINC , Use either the SHORTNAME or LONG_COMMON_NAME field for the display.",
      "mustSupport" : true,
      "binding" : {
        "strength" : "extensible"
      }
    },
    {
      "id" : "Observation.subject",
      "path" : "Observation.subject",
      "min" : 1,
      "type" : [{
        "code" : "Reference",
        "targetProfile" : ["http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient",
        "http://hl7.org/fhir/StructureDefinition/Group",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-device",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-location"],
        "_targetProfile" : [{
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : true
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        }]
      }],
      "mustSupport" : true
    },
    {
      "id" : "Observation.encounter",
      "path" : "Observation.encounter",
      "short" : "Encounter associated with Observation",
      "type" : [{
        "code" : "Reference",
        "targetProfile" : ["http://hl7.org/fhir/us/core/StructureDefinition/us-core-encounter"]
      }],
      "mustSupport" : true
    },
    {
      "id" : "Observation.effective[x]",
      "path" : "Observation.effective[x]",
      "type" : [{
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
          "valueBoolean" : true
        }],
        "code" : "dateTime"
      },
      {
        "code" : "Period"
      },
      {
        "code" : "Timing"
      },
      {
        "code" : "instant"
      }],
      "condition" : ["us-core-1"],
      "constraint" : [{
        "key" : "us-core-1",
        "severity" : "error",
        "human" : "Datetime must be at least to day.",
        "expression" : "$this is dateTime implies $this.toString().length() >= 10",
        "xpath" : "f:matches(effectiveDateTime,/\\d{4}\\d{2}\\d{2}(T\\d{2}:\\d{2}:\\d{2}(\\.\\d{3})?(Z|[-+]\\d{2}:\\d{2})?)?$/)"
      }],
      "mustSupport" : true
    },
    {
      "id" : "Observation.performer",
      "path" : "Observation.performer",
      "type" : [{
        "code" : "Reference",
        "targetProfile" : ["http://hl7.org/fhir/us/core/StructureDefinition/us-core-practitioner",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-organization",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-patient",
        "http://hl7.org/fhir/StructureDefinition/PractitionerRole",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-careteam",
        "http://hl7.org/fhir/us/core/StructureDefinition/us-core-relatedperson"],
        "_targetProfile" : [{
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : true
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        },
        {
          "extension" : [{
            "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
            "valueBoolean" : false
          }]
        }]
      }],
      "mustSupport" : true
    },
    {
      "id" : "Observation.value[x]",
      "path" : "Observation.value[x]",
      "short" : "Result Value",
      "definition" : "The clinical test or procedure result value. If a numeric value, valueQuantity.code **SHALL** be selected from [UCUM](http://unitsofmeasure.org).  A FHIR [UCUM Codes value set](http://hl7.org/fhir/STU3/valueset-ucum-units.html) that defines all UCUM codes is in the FHIR specification.",
      "type" : [{
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
          "valueBoolean" : true
        }],
        "code" : "Quantity"
      },
      {
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
          "valueBoolean" : true
        }],
        "code" : "CodeableConcept"
      },
      {
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support",
          "valueBoolean" : true
        }],
        "code" : "string"
      },
      {
        "code" : "boolean"
      },
      {
        "code" : "integer"
      },
      {
        "code" : "Range"
      },
      {
        "code" : "Ratio"
      },
      {
        "code" : "SampledData"
      },
      {
        "code" : "time"
      },
      {
        "code" : "dateTime"
      },
      {
        "code" : "Period"
      }],
      "condition" : ["us-core-2", "us-core-3"],
      "constraint" : [{
        "key" : "us-core-3",
        "severity" : "error",
        "human" : "The system SHALL be UCUM for coded quantity units.",
        "expression" : "ofType(Quantity).system.empty() or ofType(Quantity).system = 'http://unitsofmeasure.org'",
        "xpath" : "not(exists(f:valueQuantity/f:system) ) or f:valueQuantity/f:system[@value='http://unitsofmeasure.org']"
      }],
      "mustSupport" : true
    },
    {
      "id" : "Observation.dataAbsentReason",
      "path" : "Observation.dataAbsentReason",
      "condition" : ["us-core-2"],
      "mustSupport" : true
    }]
  }
}

```
