Measurements and simple assertions made about a patient, device or other subject.

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 laboratory reports, etc.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

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. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of its narrative along with other profiles, value sets, etc.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, nor can they have their own independent transaction scope. This is allowed to be a Parameters resource if and only if it is referenced by a resource that provides context/meaning.

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. Contained resources may have profiles and tags in their meta elements, but SHALL NOT have security labels.

An Extension

Other resources from the patient record that may be relevant to the event. The information from these resources was either used to create the instance or is provided to help with its interpretation. This extension should not be used if more specific inline elements or extensions are available. For example, use Observation.hasMember instead of supportingInformation for representing the members of an Observation panel.

An Extension

Source of the definition for the extension code - a logical name or a URL.

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.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

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 and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

The status of the result value.

This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

Codes providing the status of an observation.

Need to track the status of individual results. Some results are finalized before the whole report is finalized.

Describes what was observed. Sometimes this is called the observation "name".

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.

Knowing what kind of observation is being made is essential to understanding the observation.

The patient, or group of patients, location, device, organization, procedure or practitioner this observation is about and into whose or what record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

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. The subject of an Observation may in some cases be a procedure. This supports the regulatory inspection use case where observations are captured during inspections of a procedure that is being performed (independent of any particular patient or whether patient related at all).

Observations have no value if you don't know who or what they're about.

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.

At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

Knowing when an observation was deemed true is important to its relevance as well as determining trends.

The date and time this version of the observation was made available to providers, typically after the results have been reviewed and verified.

For Observations that don't require review and verification, it may be the same as the lastUpdated time of the resource itself. For Observations that do require review and verification for certain updates, it might not be the same as the lastUpdated time of the resource itself due to a non-clinically significant update that doesn't require the new version to be reviewed and verified again.

Who was responsible for asserting the observed value as "true".

May give a degree of confidence in the observation and also indicates where follow-up questions should be directed.

The information determined as a result of making the observation, if the information has a simple value.

• An observation may have:
  1. a single value here
  2. both a value and a set of related or component values
  3. only a set of related or component values.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.value[x] is missing.

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 "specimen unsatisfactory".

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. Note that an observation may only be reported if there are values to report. For example differential cell counts values may be reported only when > 0. Because of these options, use-case agreements are required to interpret general observations for null or exceptional values.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Comments about the observation or the results.

May include general statements about the observation, or statements about significant, unexpected or unreliable results values, or information about its source when relevant to its interpretation.

Need to be able to provide free text additional information.

Indicates the site on the subject's body where the observation was made (i.e. the target site).

Only used if not implicit in code found in Observation.code. In many systems, this may be represented as a related observation instead of an inline component.

The specimen that was used when this observation was made.

Should only be used if not implicit in code found in Observation.code. Observations are not made on specimens themselves; they are made on a subject, but in many cases 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 may be used in contexts that track the specimen explicitly (e.g. Diagnostic Report).

A reference to the device that generates the measurements or the device settings for the device.

Note that this is not meant to represent a device involved in the transmission of the result, e.g., a gateway. Such devices may be documented using the Provenance resource where relevant.

Guidance on how to interpret the value by comparison to a normal or recommended range. Multiple reference ranges are interpreted as an "OR". In other words, to represent two distinct target populations, two referenceRange elements would be used.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

An Extension

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Code for the specific scale or assessment used to determine the feature

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Code for the specific scale or assessment used to determine the feature

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Code for the specific scale or assessment used to determine the feature

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

Term to represent both the course and onset of a disease. Many conditions with an acute (sudden) onset also have an acute (short duration) course.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Code for the specific scale or assessment used to determine the feature

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

Whether a condition is improving, worsening, stable, or resolved.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Medication that when taken affecting the factor

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Medication that when taken affecting the factor

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

Guidance on how to interpret the value by comparison to a normal or recommended range.

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 might 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.

Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

For a discussion on the ways Observations can be assembled in groups together see Notes below.

Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

Additional notes that apply to this resource or element.

This extension SHALL NOT be used if the resource already has standard 'note' element (or equivalent) of type Annotation on the same element

Medication that when taken affecting the factor

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 in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

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.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Describes what was observed. Sometimes this is called the observation "code".

All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

Codes identifying names of simple observations.

Knowing what kind of observation is being made is essential to understanding the observation.

The information determined as a result of making the observation, if the information has a simple value.

Used when observation has a set of component observations:

• An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived).
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• If a value is present, the datatype for this element should be determined by the code.
• 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 code defines a coded value.
• Attachment is used if the observation result value is a binary file such as an image. If the observation result value is derived from the binary file (for example 'X' detected and here is the the proof in this image), the binary file may be directly represented using DocumentReference and referenced by derivedFrom.
• The usage of valueReference is restricted to the MolecularSequence resource when used as a definitional resource, not as a patient-specific finding. .
• For additional guidance, see the Notes section below.

An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

Provides a reason why the expected value in the element Observation.component.value[x] is missing.

"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.

Codes specifying why the result (Observation.value[x]) is missing.

For many results it is necessary to handle exceptional values in measurements.

A categorical assessment of an observation value. For example, high, low, normal.

Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

Codes identifying interpretations of observations.

For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.