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Used for simple observations such as device measurements, laboratory atomic results, vital
signs, height, weight, smoking status, comments, etc. Other resources are used to provide
context for observations such as Lab reports, etc.
Observations are a key aspect of healthcare. This resource is used to capture those that
do not require more sophisticated mechanisms.
The logical id of the resource, as used in the url for the resoure. Once assigned, this
value never changes.
The only time that a resource does not have an id is when it is being submitted to the
server using a create operation. Bundles always have an id, though it is usually a generated
UUID.
The metadata about the resource. This is content that is maintained by the infrastructure.
Changes to the content may not always be associated with version changes to the resource.
A reference to a set of rules that were followed when the resource was constructed, and
which must be understood when processing the content.
Asserting this rule set restricts the content to be only understood by a limited set of
trading partners. This inherently limits the usefulness of the data in the long term.
However the existing health eco-system is highly fractured, and not yet ready to define,
collect, and exchange data in a generally computable sense. Wherever possible, implementers
and/or specification writers should avoid using this element as much as possible.
Language is provided to support indexing and accessibility (typically, services such as
text to speech use the language tag). The html language tag in the narrative applies
to the narrative. The language tag on the resource may be used to specify the language
of other presentations generated from the data in the resource Not all the content has
to be in the base language. The Resource.language should not be assumed to apply to the
narrative automatically. If a language is specified, it should it also be specified on
the div element in the html (see rules in HTML5 for information about the relationship
between xml:lang and the html lang attribute).
A human-readable narrative that contains a summary of the resource, and may be used to
represent the content of the resource to a human. The narrative need not encode all the
structured data, but is required to contain sufficient detail to make it "clinically
safe" for a human to just read the narrative. Resource definitions may define what
content should be represented in the narrative to ensure clinical safety.
Contained resources do not have narrative. Resources that are not contained SHOULD have
a narrative.
These resources do not have an independent existence apart from the resource that contains
them - they cannot be identified independently, and nor can they have their own independent
transaction scope.
This should never be done when the content can be identified properly, as once identification
is lost, it is extremely difficult (and context dependent) to restore it again.
May be used to represent additional information that is not part of the basic definition
of the resource, and that modifies the understanding of the element that contains it.
Usually modifier elements provide negation or qualification. In order to make the use
of extensions safe and manageable, there is a strict set of governance applied to the
definition and use of extensions. Though any implementer is allowed to define an extension,
there is a set of requirements that SHALL be met as part of the definition of the extension.
Applications processing a resource are required to check for modifier extensions.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
The information determined as a result of making the observation, if the information has
a simple value.
Normally, an observation will have either a value or a set of related observations. A
few observations (e.g. apgar store) may have both a value and related observations (for
apgar, the observations from which the measure is derived). If a value is present, the
datatype for this element should be determined by Observation.code. A CodeableConcept
with just a text would be used instead of a string if the field was usually coded, or
if the type associated with the Observation.code defines a coded value. For boolean
values use valueCodeableConcept and select codes from <http://hl7.org/fhir/v2/vs/0136>
(These "yes/no" concepts can be mapped to the display name "true/false"
or other mutually exclusive terms that may be needed"). The element, Observation.value[x],
has a variable name depending on the type as follows: valueQuantity, valueCodeableConcept,
valueRatio, valueChoice, valuePeriod, valueSampleData, or valueString (The name format
is "'value' + the type name" with a capital on the first letter of the type).
An observation exists to have a value, though it may not if it is in error, or it represents
a group of observations.
May be used to represent additional information that is not part of the basic definition
of the element. In order to make the use of extensions safe and manageable, there is a
strict set of governance applied to the definition and use of extensions. Though any
implementer is allowed to define an extension, there is a set of requirements that SHALL
be met as part of the definition of the extension.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
The value of the measured amount. The value includes an implicit precision in the presentation
of the value.
The implicit precision in the value should always be honored. Monetary values have their
own rules for handling precision (refer to standard accounting text books).
How the value should be understood and represented - whether the actual value is greater
or less than the stated value due to measurement issues. E.g. if the comparator is "<"
, then the real value is < stated value.
This is labeled as "Is Modifier" because the comparator modifies the interpretation
of the value significantly. If there is no comparator, then there is no modification of
the value.
Need a framework for handling measures where the value is <5ug/L or >400mg/L due
to the limitations of measuring methodology.
There are many representations for units and in many contexts, particular representations
are fixed and required. I.e. mcg for micrograms.
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or
ISO 4217 for currency. The context of use may additionally require a code from a particular
system.
Need a computable form of the units that is fixed across all forms. UCUM provides this
for quantities, but SNOMED CT provides many units of interest.
"Null" or exceptional values can be represented two ways in FHIR Observations.
One way is to simply include them in the value set and represent the exceptions in the
value. For example, measurement values for a serology test could be "detected",
"not detected", "inconclusive", or "test not done". The
alternate way is to use the value element for actual observations and use the explicit
dataAbsentReason element to record exceptional values. For example, the dataAbsentReason
code "error" could be used when the measurement was not completed. Because
of these options, use-case agreements are required to interpret general observations for
exceptional values.
For some results, particularly numeric results, an interpretation is necessary to fully
understand the significance of a result.
May include statements about significant, unexpected or unreliable values, or information
about the source of the value where this may be relevant to the interpretation of the
result.
The time or time-period the observed value is asserted as being true. For biological subjects
- e.g. human patients - this is usually called the "physiologically relevant time".
This is usually either the time of the procedure or of specimen collection, but very often
the source of the date/time is not known, only the date/time itself.
Knowing when an observation was deemed true is important to its relevance as well as determining
trends.
OBX-14-date/time of the observation, and/or OBX-19 after v2.4 (depends on who observation
made)
Need to track the status of individual results - some results are finalised before the
whole report is finalised.
status Amended & Final are differentiated by whether it is the subject of a ControlAct
event with a type of "revise"
Note that in most contexts, unreliable results are not recorded, deleted, or otherwise
excluded, but it's not always possible to exclude them from the record. If the reliability
indicator is present, interpreters of a result, whether human or machine, should always
either be aware of the status or prevented from using the observation without being unaware
that the reliability is not "ok".
Codes that provide an estimate of the degree to which quality issues have impacted on
the value of an observation
Indicates the site on the subject's body where the observation was made ( i.e. the target
site).
Knowing where the observation is made is important for tracking if multiple sites are
possible.
In some cases, method can impact results and is thus for determining whether results can
be compared or determining significance of results.
The patient, or group of patients, location, or device whose characteristics (direct or
indirect) are described by the observation and into whose record the observation is placed.
Comments: Indirect characteristics may be those of a specimen, fetus, other observer
(for example a relative or EMT), or any observation made about the subject.
One would expect this element to be a cardinality of 1..1. The only circumstance in
which the subject can be missing is when the observation is made by a device that does
not know the patient. In this case, the observation SHALL be matched to a patient through
some context/channel matching technique, and at this point, the observation should be
updated. If the target of the observation is different than the subject, the general
extension (http://hl7.org/fhir/StructureDefinition/indirectTarget) can be used.
Observations are not made on specimens themselves; they are made on a subject, but usually
by the means of a specimen. Note that although specimens are often involved, they are
not always tracked and reported explicitly. Also note that observation resources are often
used in contexts that track the specimen explicitly (e.g. Diagnostic Report).
May give a degree of confidence in the observation and also indicates where follow-up
questions should be directed.
OBX.15 / (Practitioner) OBX-16-responsible observer, PRT-5-participation person:PRT-4-participatio
n='RO' / (Device) OBX-18-equipment instance identifier , PRT-10-participation device:PRT-4-particip
ation='EQUIP' / (Organization) OBX-23-performing organization name, PRT-8-participation
organization:PRT-4-participation='PO'
May give a degree of confidence in the observation and also indicates where follow-up
questions should be directed.
OBX.15 / (Practitioner) OBX-16-responsible observer, PRT-5-participation person:PRT-4-participatio
n='RO' / (Device) OBX-18-equipment instance identifier , PRT-10-participation device:PRT-4-particip
ation='EQUIP' / (Organization) OBX-23-performing organization name, PRT-8-participation
organization:PRT-4-participation='PO'
documents the name and address of the laboratory that performs the test. This is a CLIA
required item to be printed on the report, CLIA requires the name of the laboratory, city
and state of the laboratory.
May give a degree of confidence in the observation and also indicates where follow-up
questions should be directed.
OBX.15 / (Practitioner) OBX-16-responsible observer, PRT-5-participation person:PRT-4-participatio
n='RO' / (Device) OBX-18-equipment instance identifier , PRT-10-participation device:PRT-4-particip
ation='EQUIP' / (Organization) OBX-23-performing organization name, PRT-8-participation
organization:PRT-4-participation='PO'
An extension should be used if further typing of the device is needed. Devices used to
support obtaining an observation can be represented using either extension or through
the Observation.related element.
The healthcare event ( e.g. a patient and healthcare provider interaction ) during which
this observation is made.
For some observations it may be important to know the link between an observation and
a particular encounter.
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.
Knowing what values are considered "normal" can help evaluate the significance
of a particular result. Need to be able to provide multiple reference ranges for different
contexts.
May be used to represent additional information that is not part of the basic definition
of the element. In order to make the use of extensions safe and manageable, there is a
strict set of governance applied to the definition and use of extensions. Though any
implementer is allowed to define an extension, there is a set of requirements that SHALL
be met as part of the definition of the extension.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
May be used to represent additional information that is not part of the basic definition
of the element, and that modifies the understanding of the element that contains it. Usually
modifier elements provide negation or qualification. In order to make the use of extensions
safe and manageable, there is a strict set of governance applied to the definition and
use of extensions. Though any implementer is allowed to define an extension, there is
a set of requirements that SHALL be met as part of the definition of the extension. Applications
processing a resource are required to check for modifier extensions.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
The value of the low bound of the reference range. If this element is omitted, the low
bound of the reference range is assumed to be meaningless. (e.g. reference range is <2.3)
If the low.comparator element is missing, it is assumed to be '>'.
not(exists(f:comparator)) or boolean(f:comparator/@value = '<') or boolean(f:comparator/@value
= '<=')
The value of the high bound of the reference range. If this element is omitted, the high
bound of the reference range is assumed to be meaningless. (e.g. reference range is >
5) If the low.comparator element is missing , it is assumed to be '<'.
not(exists(f:comparator)) or boolean(f:comparator/@value = '>') or boolean(f:comparator/@value
= '>=')
Need to be able to say what kind of reference range this is - normal, recommended, therapeutic,
or perhaps what state this reference range applies to (i.e. age, hormonal cycles, etc.).
The age at which this reference range is applicable. This is a neonatal age (e.g. number
of weeks at term) if the meaning says so.
Text based reference range in an observation which may be used when a quantitative range
is not appropriate for an observation. An example would be a reference value of "Negative"
; or a list or table of 'normals'.
Normally, an observation will have either a value or a set of related observations. A
few observations (e.g. apgar store) may have both a value and related observations (for
apgar, the observations from which the measure is derived).
Some observations have important relationships to other observations (e.g Blood Pressure
= systolic + diastolic), or are derived from other observations (e.g. calculated apgar
score).
May be used to represent additional information that is not part of the basic definition
of the element. In order to make the use of extensions safe and manageable, there is a
strict set of governance applied to the definition and use of extensions. Though any
implementer is allowed to define an extension, there is a set of requirements that SHALL
be met as part of the definition of the extension.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
May be used to represent additional information that is not part of the basic definition
of the element, and that modifies the understanding of the element that contains it. Usually
modifier elements provide negation or qualification. In order to make the use of extensions
safe and manageable, there is a strict set of governance applied to the definition and
use of extensions. Though any implementer is allowed to define an extension, there is
a set of requirements that SHALL be met as part of the definition of the extension. Applications
processing a resource are required to check for modifier extensions.
There can be no stigma associated with the use of extensions by any application, project,
or standard - regardless of the institution or jurisdiction that uses or defines the extensions.
The use of extensions is what allows the FHIR specification to retain a core level of
simplicity for everyone.
A relationship type SHOULD be provided. If the relationship type is "COMP" (composed),
then the observation should not be displayed/interpreted in the absence of the related
observations.
May need to indicate whether this observation is composed of others, or merely derived
from them.
<?xml version="1.0" encoding="UTF-8"?>
<StructureDefinition xmlns="http://hl7.org/fhir">
<id value="iso21090-nullFlavor"/>
<extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
<valueCode value="fhir"/>
</extension>
<extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
<valueInteger value="1"/>
</extension>
<url value="http://hl7.org/fhir/StructureDefinition/iso21090-nullFlavor"/>
<version value="5.0.0-ballot"/>
<name value="nullFlavor"/>
<status value="draft"/>
<experimental value="false"/>
<date value="2012-06-24"/>
<publisher value="Health Level Seven International (Modeling and Methodology)"/>
<contact>
<telecom>
<system value="url"/>
<value value="http://www.hl7.org/Special/committees/mnm"/>
</telecom>
</contact>
<description value="If the value is not a proper value, indicates the reason."/>
<fhirVersion value="5.0.0-ballot"/>
<mapping>
<identity value="v2"/>
<uri value="http://hl7.org/v2"/>
<name value="HL7 v2 Mapping"/>
</mapping>
<mapping>
<identity value="rim"/>
<uri value="http://hl7.org/v3"/>
<name value="RIM Mapping"/>
</mapping>
<kind value="complex-type"/>
<abstract value="false"/>
<context>
<type value="element"/>
<expression value="Element"/>
</context>
<type value="Extension"/>
<baseDefinition value="http://hl7.org/fhir/StructureDefinition/Extension"/>
<derivation value="constraint"/>
<snapshot>
<element id="Extension">
<path value="Extension"/>
<short value="NI | OTH | NINF | PINF | UNK | ASKU | NAV | NASK | TRC | MSK | NA | QS"/>
<definition value="If the value is not a proper value, indicates the reason."/>
<comment value="Considerable care must be used when using nullFlavor in this context of FHIR -
more than any other concept, this is tied to the way v3 works, and FHIR is quite
different. For instance, there is no notion of a "proper value" as opposed
to any other value in FHIR. a NullFlavor should be understood to mean, "why
information is missing", and the nulFlavors OTH, NINF, PINF, and TRC should
not be used."/>
<min value="0"/>
<max value="1"/>
<base>
<path value="Extension"/>
<min value="0"/>
<max value="*"/>
</base>
<constraint>
<key value="ele-1"/>
<severity value="error"/>
<human value="All FHIR elements must have a @value or children"/>
<expression value="hasValue() or (children().count() > id.count())"/>
<xpath value="@value|f:*|h:div"/>
<source value="http://hl7.org/fhir/StructureDefinition/Element"/>
</constraint>
<constraint>
<key value="ext-1"/>
<severity value="error"/>
<human value="Must have either extensions or value[x], not both"/>
<expression value="extension.exists() != value.exists()"/>
<xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])"/>
<source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
</constraint>
<isModifier value="false"/>
<mapping>
<identity value="v2"/>
<map value="n/a"/>
</mapping>
<mapping>
<identity value="rim"/>
<map value="ANY.nullFlavor"/>
</mapping>
</element>
<element id="Extension.id">
<path value="Extension.id"/>
<representation value="xmlAttr"/>
<short value="Unique id for inter-element referencing"/>
<definition value="Unique id for the element within a resource (for internal references). This may
be any string value that does not contain spaces."/>
<min value="0"/>
<max value="1"/>
<base>
<path value="Element.id"/>
<min value="0"/>
<max value="1"/>
</base>
<type>
<extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
<valueUrl value="id"/>
</extension>
<code value="http://hl7.org/fhirpath/System.String"/>
</type>
<isModifier value="false"/>
<isSummary value="false"/>
<mapping>
<identity value="rim"/>
<map value="n/a"/>
</mapping>
</element>
<element id="Extension.extension">
<path value="Extension.extension"/>
<slicing>
<discriminator>
<type value="value"/>
<path value="url"/>
</discriminator>
<description value="Extensions are always sliced by (at least) url"/>
<rules value="open"/>
</slicing>
<short value="Extension"/>
<definition value="An Extension"/>
<min value="0"/>
<max value="0"/>
<base>
<path value="Element.extension"/>
<min value="0"/>
<max value="*"/>
</base>
<type>
<code value="Extension"/>
</type>
<constraint>
<key value="ele-1"/>
<severity value="error"/>
<human value="All FHIR elements must have a @value or children"/>
<expression value="hasValue() or (children().count() > id.count())"/>
<xpath value="@value|f:*|h:div"/>
<source value="http://hl7.org/fhir/StructureDefinition/Element"/>
</constraint>
<constraint>
<key value="ext-1"/>
<severity value="error"/>
<human value="Must have either extensions or value[x], not both"/>
<expression value="extension.exists() != value.exists()"/>
<xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), "value")])"/>
<source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
</constraint>
<isModifier value="false"/>
<isSummary value="false"/>
</element>
<element id="Extension.url">
<path value="Extension.url"/>
<representation value="xmlAttr"/>
<short value="identifies the meaning of the extension"/>
<definition value="Source of the definition for the extension code - a logical name or a URL."/>
<comment value="The definition may point directly to a computable or human-readable definition
of the extensibility codes, or it may be a logical URI as declared in some other
specification. The definition SHALL be a URI for the Structure Definition defining
the extension."/>
<min value="1"/>
<max value="1"/>
<base>
<path value="Extension.url"/>
<min value="1"/>
<max value="1"/>
</base>
<type>
<extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
<valueUrl value="uri"/>
</extension>
<code value="http://hl7.org/fhirpath/System.String"/>
</type>
<fixedUri value="http://hl7.org/fhir/StructureDefinition/iso21090-nullFlavor"/>
<isModifier value="false"/>
<isSummary value="false"/>
<mapping>
<identity value="rim"/>
<map value="N/A"/>
</mapping>
</element>
<element id="Extension.value[x]">
<path value="Extension.value[x]"/>
<short value="Value of extension"/>
<definition value="Value of extension - must be one of a constrained set of the data types (see [Extensibility](
extensibility.html) for a list)."/>
<min value="1"/>
<max value="1"/>
<base>
<path value="Extension.value[x]"/>
<min value="0"/>
<max value="1"/>
</base>
<type>
<code value="code"/>
</type>
<constraint>
<key value="ele-1"/>
<severity value="error"/>
<human value="All FHIR elements must have a @value or children"/>
<expression value="hasValue() or (children().count() > id.count())"/>
<xpath value="@value|f:*|h:div"/>
<source value="http://hl7.org/fhir/StructureDefinition/Element"/>
</constraint>
<isModifier value="false"/>
<isSummary value="false"/>
<binding>
<extension url="http://hl7.org/fhir/build/StructureDefinition/binding-definition">
<valueString value="A collection of codes specifying why a valid value is not present."/>
</extension>
<extension url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
<valueString value="NullFlavor"/>
</extension>
<strength value="required"/>
<valueSet value="http://terminology.hl7.org/ValueSet/v3-NullFlavor|2.0.0"/>
</binding>
<mapping>
<identity value="rim"/>
<map value="N/A"/>
</mapping>
</element>
</snapshot>
<differential>
<element id="Extension">
<path value="Extension"/>
<short value="NI | OTH | NINF | PINF | UNK | ASKU | NAV | NASK | TRC | MSK | NA | QS"/>
<definition value="If the value is not a proper value, indicates the reason."/>
<comment value="Considerable care must be used when using nullFlavor in this context of FHIR -
more than any other concept, this is tied to the way v3 works, and FHIR is quite
different. For instance, there is no notion of a "proper value" as opposed
to any other value in FHIR. a NullFlavor should be understood to mean, "why
information is missing", and the nulFlavors OTH, NINF, PINF, and TRC should
not be used."/>
<min value="0"/>
<max value="1"/>
<mapping>
<identity value="v2"/>
<map value="n/a"/>
</mapping>
<mapping>
<identity value="rim"/>
<map value="ANY.nullFlavor"/>
</mapping>
</element>
<element id="Extension.extension">
<path value="Extension.extension"/>
<max value="0"/>
</element>
<element id="Extension.url">
<path value="Extension.url"/>
<fixedUri value="http://hl7.org/fhir/StructureDefinition/iso21090-nullFlavor"/>
</element>
<element id="Extension.value[x]">
<path value="Extension.value[x]"/>
<min value="1"/>
<type>
<code value="code"/>
</type>
<binding>
<extension url="http://hl7.org/fhir/build/StructureDefinition/binding-definition">
<valueString value="A collection of codes specifying why a valid value is not present."/>
</extension>
<extension url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
<valueString value="NullFlavor"/>
</extension>
<strength value="required"/>
<valueSet value="http://terminology.hl7.org/ValueSet/v3-NullFlavor|2.0.0"/>
</binding>
</element>
</differential>
</StructureDefinition>
</
StructureDefinition
>
Usage
note:
every
effort
has
been
made
to
ensure
that
the
examples
are
correct
and
useful,
but
they
are
not
a
normative
part
of
the
specification.
Foundation
.
Page
versions:
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R4
R3
R2
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Propose
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