Appears in
- Laboratory Test Observation and Specimen Transportation
- Medical Imaging Reporting
- Medical Device and Equipment
- Health Event
- Perinatal Health
- Encounter
- Vital Signs
- Observation
- Procedure
- Immunization
- Social Determinants of Health (SDOH) Assessment
- Service Request
- Appointment
- Laboratory Test Result Reporting
- Substance Use
- CACDI View
Constraints
Unique key(s)
- XOR (Patient, Party Group, Organization, Location, Standardized Assessment, Device), Observation Code, Observation Date Time
- XOR("Observation Value *" attributes)
Stereotype(s)
n/a
Attributes
| Attribute | Type | Multiplicity | Attribute note |
|---|---|---|---|
| Observation Code | Codeable Concept | 1 | Uniquely specifies what was observed. Sometimes called "observation name".
Value Set: To be developed. |
| Observation Date Time | Date Time | 1 | The date and time when the observation occurred. |
| Observation Category Code | Codeable Concept | 0..1 | Uniquely specifies the classification for the observation (e.g., social history, vital signs, imaging).
Value Set: To be developed. |
| Observation Interpretation Type Code | Codeable Concept | 0..* | Uniquely specifies rough qualitative interpretation(s) of the observation value (e.g., better, worse, significant change up, significant change down).
Value Set: To be developed. |
| Observation Status Code | Codeable Concept | 0..1 | Uniquely specifies the status of the observation (e.g., registered, preliminary, final).
Value Set: To be developed. |
| Observation Body Site Code | Codeable Concept | 0..1 | Uniquely specifies the site on the subject's body where the observation was made (i.e., the target site).
Values set are context (observation) specific.
Examples of blood pressure body locations include the right upper arm, left upper arm, entire right thigh, and entire left femoral artery.
Value Set: To be developed. |
| Observation Measurement Type Code | Codeable Concept | 0..1 | Uniquely specifies whether the observation value is measured, estimated, or calculated.
Value Set: To be developed. |
| Observation Measurement Method Code | Codeable Concept | 0..1 | Uniquely specifies the mechanism used to perform the observation.
Values set are context (observation) specific.
Body temperature measurement methods include using a tympanic thermometer and a skin strip thermometer. Blood pressure measurement methods include ambulatory blood pressure recording, blood pressure recorded by the patient at home, and measurement of blood pressure at the anterior tibial pulse using a doppler.
Value Set: To be developed. |
| Observation Value Code | Codeable Concept | 0..1 | Uniquely specifies the actual value of the observation (as a code from a code system in a value set).
The value set is specific to the observation being captured.
Value Set: To be developed.
Laboratory Observation Value Set:
https://fhir.infoway-inforoute.ca/ValueSet/labobservationvaluecode |
| Observation Value Quantity | Quantity | 0..1 | The actual value of the observation (as a decimal quantity).
Quantity.Unit of Measure Code is optional, and not applicable when the observation code already states or presupposes a specific unit of measure.
For Laboratory Result Observations:
Unit of Measure Code
Value Sets:
https://fhir.infoway-inforoute.ca/ValueSet/laboratoryobservationunitofmeasurecode
https://ui.terminologystandardsservice.ca/ui/deeplink?iss=https://terminologystandardsservice.ca/fhir&type=ValueSet&canonicalUrl=https://fhir.infoway-inforoute.ca/ValueSet/x_timeunitsofmeasure
|
| Observation Value Integer | Integer | 0..1 | The actual value of the observation (as an integer). |
| Observation Value Date Time | Date Time | 0..1 | The actual value of the observation (as date time).
Note: the time part is optional; the date part can have any of following granularities (in any format): (i) year, month, day; or year, day of year (ii) year, month; (iii) year only. |
| Observation Value Time | Time | 0..1 | The actual value of the observation (as time: 1 or more of hours, minutes, seconds, fractions of seconds). |
| Observation Value Description | String | 0..1 | The actual value of the observation (as a textual description). |
| Observation Value Range | Range | 0..1 | The actual value of the observation (as a range).
Range.Unit of Measure Code, for both low end and high end, is optional, and not applicable when the observation code already states or presupposes a specific unit of measure. |
| Observation Value Ratio | Ratio | 0..1 | The actual value of the observation (as a ratio).
Ratio.Unit of Measure Code, for both numerator and denominator, is optional, and not applicable when the observation code already states or presupposes a specific unit of measure. |
| Observation Value Indicator | Indicator | 0..1 | The actual value of the observation (as an indicator). |
| Observation Value Sampled Data | Sampled Data | 0..1 | The actual value of the observation (as sampled data: origin (zero/baseline decimal value and unit of measure), period between samples (milliseconds), dimensions, and optionally one or more of: factor, lower limit of detection, upper limit of detection, data as string). |
| Observation Value Period | Period | 0..1 | The actual value of the observation (as a period). |
Relationships
| From class | From multiplicity | Relationship | To class | To multiplicity |
|---|---|---|---|---|
| Procedure Reason | 0..* | is | Observation | 0..1 |
| Observation | 0..1 | has (composition) | Clinical Annotation | 0..* |
| Party Role | 0..1 | performer | Observation | 0..* |
| Location | 0..1 | subject of | Observation | 0..* |
| Observation | 0..* | has (composition) | Observation Component | 0..* |
| Observation | 0..* | references {All observations on the same patient} |
Patient Pregnancy | 0..1 |
| Observation | is a | Clinical Event | ||
| Observation | 0..* | has (composition) | Observation Reference Range | 0..* |
| Vital Sign Set | 0..* | uses {=1 Patient for all related observations} |
Observation | 0..* |
| Obstetrical History | 0..* | uses | Observation | 0..* |
| Device | 0..1 | subject of | Observation | 0..* |
| Party Group | 0..1 | subject of | Observation | 0..* |
| Encounter Reason | 0..* | is | Observation | 0..1 |
| Observation | 0..* | about | Specimen | 0..1 |
| Observation | 0..* | derived from | Clinical Document | 0..* |
| Service Request Reason | 0..* | is | Observation | 0..1 |
| Patient | 0..1 | subject of | Observation | 0..* |
| Procedure Context | 0..* | is | Observation | 0..1 |
| Diagnostic Report | 0..1 | associated with | Observation | 0..* |
| Organization | 0..1 | subject of | Observation | 0..* |
| Observation | 0..* | generated by | Device | 0..1 |
| Observation | 0..* | derived from | Document Reference | 0..* |
| Patient Immunization Reaction | 0..1 | evidenced by | Observation | 0..1 |
| Standardized Assessment | 0..1 | subject of | Observation | 0..* |
Contact us
If you have questions about this initiative, would like to be added to our stakeholder notification list or would like to participate in our consultations, please email us.
How to cite:
Canadian Institute for Health Information. Observation. Accessed November 02, 2026.
