Example Usage Scenarios:

The following are example usage scenarios for this profile:

• Query for lab results belonging to a Patient
• Record or update lab results belonging to a Patient

Mandatory and Must Support Data Elements

In addition to the Mandatory and Must Support data elements in the US Core Observation Clinical Result Profile, the following data elements must always be present (Mandatory definition) or must be supported if the data is present in the sending system (Must Support definition). They are presented below in a simple human-readable explanation. Profile specific guidance and examples are provided as well. The Formal Views section below provides the formal summary, definitions, and terminology requirements. Note that the "Differential Table" displays elements unique to this profile and the "Key Elements Table” displays a combined view of elements for this profile and the US Core Observation Clinical Result Profile.

Each Observation Must Have:

1. a category code of 'laboratory'
2. a laboratory LOINC code, if available, which tells you what is being measured

Each Observation Must Support:

1. a timestamp when the resource last changed*
2. a result value*
   • if the result value is a numeric quantity, a standard UCUM unit
   • if the result value is a coded quantity, a standard SNOMED CT
3. result interpretation
   • if the result value is a numeric quantity, a standard UCUM unit
4. result reference range
5. a specimen type (e.g., blood, serum, urine)

* see guidance below

Profile Specific Implementation Guidance:

• For USCDI, systems are required to use SNOMED CT for coded results if the SCT code exists.
• The specimen type can be communicated in the mandatory Observation.code (e.g., Blood Glucose), the Must Support Observation.specimen element, or through both elements.

• The Observation.category element provides an efficient way of restricting search on observations to a given context such as laboratory observations. Example searches are shown in the Quick Start 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.
• Additional codes that translate or map to the Observation code or category codes are allowed. For example:
  • providing both a local code and a LOINC code
  • providing a more specific code such as 'chemistry', a SNOMED CT concept, or a system-specific code
• Systems SHOULD support Observation.effectivePeriod to accurately represent measurements over time (for example, a 24-Hour Urine Collection test).
• *An 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.
  • For further guidance, see the Observation Grouping section in FHIR Specification.
  • Systems that never provide an observation without a value are not required to support Observation.dataAbsentReason.
• *An Observation.component without a value, SHALL include a reason why the data is absent.
  • Systems that never provide a component observation without a component value are not required to support Observation.component.dataAbsentReason.
• See the General Guidance page for further guidance on SNOMED and UCUM.
• See the LOINC scale type to FHIR data type mapping for guidance on which Observation.value[x] data type to use based on the LOINC Type of Scale.

• *This profile inherits the invariant "us-core-3" from the US Core Observation Clinical Result Profile that requires UCUM to be used as a unit type for Observation.valeQuantity.code.
• * See the US Core General Guidance page for Searching Using lastUpdated. Updates to Meta.lastUpdated SHOULD reflect:
  • New laboratory observations
  • Changes in the status of laboratory observations, including events that trigger the same status (e.g., amended → amended).

Changes since version 7.0.0:

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 for a complete list of supported RESTful interactions for this IG.

• See the Scopes Format section for a description of the SMART scopes syntax.
• See the Search Syntax section for a description of the US Core search syntax.
• See the General Requirements section for additional rules and expectations when a Server requires status parameters.
• See the General Guidance section for additional guidance on searching for multiple patients.

US Core Scopes

Servers providing access to laboratory data SHALL support these US Core SMART Scopes:

• resource level scopes: <patient|user|system>/Observation.rs

• granular scopes: <patient|user|system>/Observation.rs?category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory

Mandatory Search Parameters:

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

1. SHALL support searching using the combination of the patient and category search parameters:

   GET [base]/Observation?patient={Type/}[id]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory

   Example:

   1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and a category code = laboratory (how to search by reference and how to search by token)

2. SHALL support searching using the combination of the patient and code search parameters:
   • including optional support for OR search on code (e.g.code={system|}[code],{system|}[code],...)

   GET [base]/Observation?patient={Type/}[id]&code={system|}[code]{,{system|}[code],...}

   Example:

   1. GET [base]/Observation?patient=1134281&code=http://loinc.org|2339-0
   2. GET [base]/Observation?patient=1134281&code=http://loinc.org|2339-0,http://loinc.org|25428-4,http://loinc.org|2514-8

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and observation code(s). SHOULD support search by multiple report codes. The Observation code parameter searches `Observation.code only. (how to search by reference and how to search by token)

3. SHALL support searching using the combination of the patient and category and date search parameters:
   • including support for these date comparators: gt,lt,ge,le
   • including optional support for AND search on date (e.g.date=[date]&date=[date]]&...)

   GET [base]/Observation?patient={Type/}[id]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

   Example:

   1. GET [base]Observation?patient=555580&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&date=ge2018-03-14T00:00:00Z

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and a category code = laboratory (how to search by reference and how to search by token and how to search by date)

Optional Search Parameters:

The following search parameter combinations SHOULD be supported:

1. SHOULD support searching using the combination of the patient and category and status search parameters:
   • including support for OR search on status (e.g.status={system|}[code],{system|}[code],...)

   GET [base]/Observation?patient={Type/}[id]&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&status={system|}[code]{,{system|}[code],...}

   Example:

   1. GET [base]/Observation?patient=1134281&category=http://terminology.hl7.org/CodeSystem/observation-category|laboratory&status=final

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and category = laboratory and status (how to search by reference and how to search by token)

2. SHOULD support searching using the combination of the patient and category and _lastUpdated search parameters:
   • including support for these _lastUpdated comparators: gt,lt,ge,le
   • including optional support for AND search on _lastUpdated (e.g._lastUpdated=[date]&_lastUpdated=[date]]&...)

   GET [base]/Observation?patient={Type/}[id]&category={system|}[code]&_lastUpdated={gt|lt|ge|le}[date]{&_lastUpdated={gt|lt|ge|le}[date]&...}

   Example:

   1. GET [base]Observation?patient=555580&http://terminology.hl7.org/CodeSystem/observation-category|laboratory&_lastUpdated=ge2024-01-01T00:00:00Z

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and category and _lastUpdated. See the US Core General Guidance page for Searching Using lastUpdated. (how to search by reference and how to search by token and how to search by date)

3. SHOULD support searching using the combination of the patient and code and date search parameters:
   • including optional support for OR search on code (e.g.code={system|}[code],{system|}[code],...)
   • including support for these date comparators: gt,lt,ge,le
   • including optional support for AND search on date (e.g.date=[date]&date=[date]]&...)

   GET [base]/Observation?patient={Type/}[id]&code={system|}[code]{,{system|}[code],...}&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

   Example:

   1. GET [base]Observation?patient=555580&code=http://loinc.org|2339-0&date=ge2019-01-01T00:00:00Z

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and report code(s). SHOULD support search by multiple report codes. (how to search by reference and how to search by token and how to search by date)