## Observation Profiles
### Scope and Usage
These Observation profiles are part of the Point-of-Care Device General Implementation Guide. Observation resources report the actual measured or calculated values, status, or settings of a medical device.

Other profiles may apply as well, e. g. the [Vital Signs Profile](http://hl7.org/fhir/observation-vitalsigns.html) from FHIR Core specification.

A compliant device shall report physiological measurements, calculations, status, and settings as [Observation](http://hl7.org/fhir/observation.html) resources according to the Numeric, Compound Numeric, Enumeration, and Sample Array Observation profiles. The profiles define the following rules:
* `Observation.code` and, for compound metrics, `Observation.component.code` shall have a coding from the ISO/IEEE 11073 MDC metrics nomenclature. The [Rosetta Terminology Mapping Management System](https://rtmms.nist.gov/rtmms/index.htm) (RTMMS) lists available codes. Depending on the type of measurement, the Vital Signs profiles may require an additional LOINC code.
* `Observation.subject` shall be present and refer to a Patient resource or PoC Device resource.
* The Measurement Status extension provides more detailed status information about observed values. It gets a code from the Measurement Status value set.
* Numeric Observation resources represent simple numerical measurements, calculations, or settings:
  * Either `Observation.valueQuantity` or `Observation.valueRatio` or, if there is no value, `Observation.dataAbsentReason` shall be present. Values shall have a UCUM unit code.
  * `Observation.device` shall be present and refer to the Numeric DeviceMetric resource where this observation belongs to.
* Compound Numeric Observation resources represent numerical measurements, calculations, or settings with multiple components:
  * `Observation.value[x]` must not be there.
  * `Observation.device` shall be present and refer to the Numeric DeviceMetric resource where this observation belongs to.
  * One or more `Observation.component` shall be present.
  * For each component, `Observation.component.valueQuantity` or, if there is no value, `Observation.component.dataAbsentReason` shall be present. Values shall have a UCUM unit code.
* Enumeration Observation resources represent status or annotation information as codes or text:
  * Either `Observation.valueCodeableConcept` or `Observation.valueString` or, if there is no value, `Observation.dataAbsentReason` shall be present.
  * `Observation.device` shall be present and refer to the Enumeration DeviceMetric resource where this observation belongs to.
* Sample Array Observation resources represent real-time waveforms or wave snippets:
  * *(to be completed)*

### Content
|StructureDefinition|Description|Example|
|---|---|---|
|{{link:DoF-PoCD/NumericObservation}}|Actual value of a numerical measurement, calculation, or setting|{{link:DoF-PoCD/HeartRateNumericObservation-example}}|
|{{link:DoF-PoCD/CompoundNumericObservation}}|Actual value of a numerical measurement, calculation, or setting with multiple components|{{link:DoF-PoCD/NBPCompoundNumericObservation-example}}|
|{{link:DoF-PoCD/EnumerationObservation}}|Actual value of status or annotation information as codes or text|{{link:DoF-PoCD/RhythmStatusEnumerationObservation-example}}|
|Sample Array Observation Profile *(to be completed)*|Actual value (wave samples) of a real-time waveform or wave snippet| |

|Extension|Description|Example|
|---|---|---|
|{{link:Dof-PoCD/observation-measurement-status}}|Status information about the observed value|{{link:DoF-PoCD/SpO2NumericObservation-example}}|