Observation Profile

Canonical	../StructureDefinition/nexus-emr-core-observation
Status	draft · 1.26.0
Base	Observation (constraint)
Source	FSH · JSON

Nexus EMR profile for the Observation resource, based on CA-Core. Represents measurements, tests, and simple assertions originating from source EMRs for aggregation.

Salient fields

The profile's synthesized-accessor contract: fields TypedFhir surfaces as first-class typed properties, each computed from the instance by a restricted FHIRPath expression. See Salient Fields for what they are, how they shape LLM contexts, and how to declare them.

Key	Type	Expression	Rendered as	Description
code	coded	code		Observation type with raw code support i
value	quantity	value		Actual observation result i
value_text	string	valueString \| valueCodeableConcept.text \| valueCodeableConcept.coding.first().display \| valueBoolean \| valueInteger \| valueDateTime \| valuePeriod.start \| valueTime	value	Actual observation result i
date	dateTime	date		Clinically relevant time of the observation i
status	code	status		Where the result is in its lifecycle i
interpretation	coded	interpretation		High, low, normal, etc. i

code

Short	Observation type with raw code support
Definition	Type of observation (e.g., vital sign, laboratory test, imaging observation). REQUIRED: text element for human readability RECOMMENDED: LOINC code when available OPTIONAL: Raw EMR observation codes for source system preservation Nexus EMR does not mandate a specific coding system for observations. The text element ensures human readability even when coded values are not recognized. Where this code was mapped from a source system's own vocabulary, carry the raw coding alongside the mapped one, flagged userSelected = true. See Carrying the raw code.
Comments	All code-value and, if present, component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.
Expression	code
Type	coded
Prose inherited from	Observation.code

value

Short	Actual observation result
Definition	The actual value of the observation. The data type varies based on the nature of the observation.
Comments	Use the appropriate data type: Quantity for measurements, CodeableConcept for coded results, string for text results, etc.
Expression	value
Type	quantity
Prose inherited from	Observation.value[x]

value_text

Short	Actual observation result
Definition	The actual value of the observation. The data type varies based on the nature of the observation.
Comments	Use the appropriate data type: Quantity for measurements, CodeableConcept for coded results, string for text results, etc.
Expression	valueString | valueCodeableConcept.text | valueCodeableConcept.coding.first().display | valueBoolean | valueInteger | valueDateTime | valuePeriod.start | valueTime
Type	string
Prose inherited from	Observation.value[x]

date

Short	Clinically relevant time of the observation
Comments	Reads Observation.effective[x]: effectiveDateTime, or the start of effectivePeriod. This is the time the observation APPLIES to, not when it was recorded -- use meta.lastUpdated or Observation.issued for that.
Expression	date
Type	dateTime

status

Short	Where the result is in its lifecycle
Definition	The status of the result value. Indicates whether the observation is complete and verified.
Comments	This is a modifier element. Preliminary results should be interpreted with caution.
Expression	status
Type	code
Prose inherited from	Observation.status

interpretation

Short	High, low, normal, etc.
Definition	A categorical assessment of an observation value. Common interpretations include high, low, normal, abnormal, critical.
Comments	Multiple interpretations may be provided for different aspects of the result.
Expression	interpretation
Type	coded
Prose inherited from	Observation.interpretation