This page is part of the FHIR Specification (v0.0.82: DSTU 1). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5R4BR4R3R2
Measurements and simple assertions made about a patient, device or other subject.
4.15.1 Scope and Usage
Observations are a central element in healthcare, used to support diagnosis, monitor progress, determine baselines and patterns
and even capture demographic characteristics. Most observations are simple name/value pair assertions with some metadata,
but some observations group other observations together logically, or even are multi-component observations.
Note that the resources DiagnosticReport and DeviceObservationReport
provide a clinical or workflow context for a set of observations. Expected uses for the Observation resource include:
Personal characteristics: height, weight, eye-color
Diagnoses (Note: trackable conditions, allergies, adverse reactions and more complex structures are handled elsewhere)
Social history: tobacco use, family supports, cognitive status
Core characteristics: pregnancy status, death assertion
4.15.2 Background and Context
The observation resource has the following aspects:
status and reliability (mandatory) - all users of observations SHALL be sure of the status of the observation
name (mandatory) - describes what was observed. Sometimes called this is called the observation "code"
identifier - Unique identifier for this particular observation so it can be recognized in all contexts where it is represented
value - the actual value that was observed
related observations - Other observations that are components of this observation, or provide supporting information, context or warnings about this observation
subject, bodysite - the patient, or group of patients, location, or device, that this observation was made on. Note that group of patients is most often used in veterinary care. For individual patients, the location on the body may also be specified, though this is often implicit in the Observation.name
applies[x] - the time or period that this observation was made on the subject. Each observation has multiple times - prepared, made, reported etc - but the important time is when the data relates to the patient condition
interpretation, comments, and reference range: information to help understand the observed value
method, issued, performer - additional information about how the test was performed that may help understand the observation. The method is often implicit in the Observation.name
Typically, an observation will have either a value or component observations, and not both.
Inv-2: Can only have normal range if value is a quantity (xpath: exists(f:valueQuantity) or not(exists(f:normalRange)))
Inv-3: On Observation.referenceRange: Must have at least a low or a high (and no comparators) (xpath on f:Observation/f:referenceRange: (exists(f:low) or exists(f:high)) and not(exists(f:low/f:comparator)) and not(exists(f:high/f:comparator)))
4.15.4 Notes:
The element, Observation.value[x], has a variable name depending on the type as follows:
valueQuantity
valueCodeableConcept
valueAttachment
valueRatio
valuePeriod
valueSampledData
valueString
The appliesDateTime or appliesPeriod is the time that the observation is most
relevant as an observation of the subject. For a biological subject (e.g. a human patient),
this is the physiologically relevant time of the observation.
In the case of an observation using a specimen, this represents the start and
end of the specimen collection (e.g. 24 hour Urine Sodium), but if the collection time is
sufficiently short, this is reported as a point in time value (e.g. normal venepuncture).
In the case of an observation obtained directly from a subject (e.g., BP,
Chest X-ray), this is the start and end time of the observation process, which again, is
often reported as a single point in time.
At its simplest, resource instances can consist of only a type and a value, with a reliability and status flag.
The relevance of other properties will vary based on the type of observation.
Reference ranges may be useful for lab tests and other measures like systolic blood pressure, but will have little
relevance for something like "pregnancy status"
Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g. specific to the patient's age, gender, weight and other factors), but this may not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties
Profiles will be created to provide guidance on capturing certain types
of simple observations. This resource focuses on the level of detail
captured by most systems. However, any "simple" observation can easily
be broken into numerous components and sub-components to provide additional
information relevant in certain circumstances. As with other resources,
extensions can be used to introduce this additional complexity.
Because there are multiple types allowed for the value element, multiple value search parameters are defined. There is no standard parameter for searching values of type Attachment, or Ratio
4.15.5 Search Parameters
Search parameters for this resource. The standard parameters also apply. See Searching for more information about searching in REST, messaging, and services.
. Page versions: R5 R4B R4 R3 R2
<!-- from Resource: extension, modifierExtension, language, text, and contained --> <name><!-- 1..1 CodeableConcept Type of observation (code / type) --></name> <value[x]><!-- 0..1 Quantity|CodeableConcept|Attachment|Ratio|Period| SampledData|string Actual result --></value[x]> <interpretation><!-- 0..1 CodeableConcept High, low, normal, etc. --></interpretation> <comments value="[string]"/><!-- 0..1 Comments about result --> <applies[x]><!-- 0..1 dateTime|Period Physiologically Relevant time/time-period for observation --></applies[x]> <issued value="[instant]"/><!-- 0..1 Date/Time this was made available --> <status value="[code]"/><!-- 1..1 registered | preliminary | final | amended + --> <reliability value="[code]"/><!-- 1..1 ok | ongoing | early | questionable | calibrating | error + --> <bodySite><!-- 0..1 CodeableConcept Observed body part --></bodySite> <method><!-- 0..1 CodeableConcept How it was done --></method> <identifier><!-- 0..1 Identifier Unique Id for this particular observation --></identifier> <subject><!-- 0..1 Resource(Patient|Group|Device|Location) Who and/or what this is about --></subject> <specimen><!-- 0..1 Resource(Specimen) Specimen used for this observation --></specimen> <performer><!-- 0..* Resource(Practitioner|Device|Organization) Who did the observation --></performer> <referenceRange> <!-- 0..* Provides guide for interpretation --> <low><!--
0..1 Quantity Low Range, if relevant --></low> <high><!--
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