# text.div
Name | Flags | Card. | Type | Description & Constraints
AllergyIntolerance | | 0..* | AllergyIntolerance | Allergy or Intolerance (generally: Risk of adverse reaction to a substance)

clinicalStatus

S

0..1

CodeableConcept

active | inactive | resolved
Binding: AllergyIntoleranceClinicalStatusCodes (required)

verificationStatus

S

0..1

CodeableConcept

unconfirmed | confirmed | refuted | entered-in-error
Binding: AllergyIntoleranceVerificationStatusCodes (required)

code

S

1..1

CodeableConcept

Code that identifies the allergy or intolerance
Binding: Common substances for allergy and intolerance documentation including refutations (extensible)

patient | S | 1..1 | Reference(US Core Patient Profile) | Who the sensitivity is for
reaction | S | 0..* | BackboneElement | Adverse Reaction Events linked to exposure to substance

manifestation

S

1..*

CodeableConcept

Clinical symptoms/signs associated with the Event
Binding: SNOMEDCTClinicalFindings (extensible)

Documentation for this format

# publisher
HL7 International - Cross-Group Projects

# contact[].name
HL7 International - Cross-Group Projects

# description
To promote interoperability and adoption through common implementation, this profile sets minimum expectations for the AllergyIntolerance resource to record, search, and fetch allergies/adverse reactions associated with a patient pm2.  It identifies the mandatory core elements, extensions, vocabularies and value sets which **SHALL** be present in the AllergyIntolerance resource when using this profile. It provides the floor for standards development for specific uses cases.

# copyright
Used by permission of HL7 International, all rights reserved Creative Commons License

# snapshot.element[].short
Allergy or Intolerance (generally: Risk of adverse reaction to a substance)

# snapshot.element[].constraint[].human
AllergyIntolerance.clinicalStatus SHALL NOT be present if verification Status is entered-in-error

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain nested Resources

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a security label

# snapshot.element[].constraint[].extension[].valueMarkdown
When a resource has no narrative, only systems that fully understand the data can display the resource to a human safely. Including a human readable representation in the resource makes for a much more robust eco-system and cheaper handling of resources by intermediary systems. Some ecosystems restrict distribution of resources to only those systems that do fully understand the resources, and as a consequence implementers may believe that the narrative is superfluous. However experience shows that such eco-systems often open up to new participants over time.

# snapshot.element[].constraint[].human
A resource should have narrative for robust management

# snapshot.element[].definition
The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

# snapshot.element[].comment
The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

# snapshot.element[].definition
The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
A set of rules under which this content was created

# snapshot.element[].definition
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.

# snapshot.element[].comment
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 it's narrative along with other profiles, value sets, etc.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation

# snapshot.element[].definition
The base language in which the resource is written.

# snapshot.element[].comment
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).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Text summary of the resource, for human interpretation

# snapshot.element[].definition
A human-readable narrative that contains a summary of the resource and can 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.

# snapshot.element[].comment
Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied).  This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the resource. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
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 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.

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

# snapshot.element[].comment
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.

# snapshot.element[].requirements
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](http://hl7.org/fhir/R4/extensibility.html#modifierExtension).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].isModifierReason
Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them

# snapshot.element[].definition
Business identifiers assigned to this AllergyIntolerance by the performer or other systems which remain constant as the resource is updated and propagates from server to server.

# snapshot.element[].comment
This is a business identifier, not a resource identifier (see [discussion](http://hl7.org/fhir/R4/resource.html#identifiers)).  It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types.  For example, multiple Patient and a Person resource instance might share the same social insurance number.

# snapshot.element[].requirements
Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The clinical status of the allergy or intolerance.

# snapshot.element[].comment
Refer to [discussion](http://hl7.org/fhir/R4/extensibility.html#Special-Case) if clincalStatus is missing data.
The data type is CodeableConcept because clinicalStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
This element is labeled as a modifier because the status contains the codes inactive and resolved that mark the AllergyIntolerance as no longer active.

# snapshot.element[].short
unconfirmed | confirmed | refuted | entered-in-error

# snapshot.element[].definition
Assertion about certainty associated with the propensity, or potential risk, of a reaction to the identified substance (including pharmaceutical product).

# snapshot.element[].comment
The data type is CodeableConcept because verificationStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
This element is labeled as a modifier because the status contains the codes refuted and entered-in-error that mark the AllergyIntolerance as not currently valid.

# snapshot.element[].short
allergy | intolerance - Underlying mechanism (if known)

# snapshot.element[].definition
Identification of the underlying physiological mechanism for the reaction risk.

# snapshot.element[].comment
Allergic (typically immune-mediated) reactions have been traditionally regarded as an indicator for potential escalation to significant future risk. Contemporary knowledge suggests that some reactions previously thought to be immune-mediated are, in fact, non-immune, but in some cases can still pose a life threatening risk. It is acknowledged that many clinicians might not be in a position to distinguish the mechanism of a particular reaction. Often the term "allergy" is used rather generically and may overlap with the use of "intolerance" - in practice the boundaries between these two concepts might not be well-defined or understood. This data element is included nevertheless, because many legacy systems have captured this attribute. Immunologic testing may provide supporting evidence for the basis of the reaction and the causative substance, but no tests are 100% sensitive or specific for sensitivity to a particular substance. If, as is commonly the case, it is unclear whether the reaction is due to an allergy or an intolerance, then the type element should be omitted from the resource.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Identification of the underlying physiological mechanism for a Reaction Risk.

# snapshot.element[].short
food | medication | environment | biologic

# snapshot.element[].comment
This data element has been included because it is currently being captured in some clinical systems. This data can be derived from the substance where coding systems are used, and is effectively redundant in that situation.  When searching on category, consider the implications of AllergyIntolerance resources without a category.  For example, when searching on category = medication, medication allergies that don't have a category valued will not be returned.  Refer to [search](http://hl7.org/fhir/R4/search.html) for more information on how to search category with a :missing modifier to get allergies that don't have a category.  Additionally, category should be used with caution because category can be subjective based on the sender.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Category of an identified substance associated with allergies or intolerances.

# snapshot.element[].definition
Estimate of the potential clinical harm, or seriousness, of the reaction to the identified substance.

# snapshot.element[].comment
The default criticality value for any propensity to an adverse reaction should be 'Low Risk', indicating at the very least a relative contraindication to deliberate or voluntary exposure to the substance. 'High Risk' is flagged if the clinician has identified a propensity for a more serious or potentially life-threatening reaction, such as anaphylaxis, and implies an absolute contraindication to deliberate or voluntary exposure to the substance. If this element is missing, the criticality is unknown (though it may be known elsewhere).  Systems that capture a severity at the condition level are actually representing the concept of criticality whereas the severity documented at the reaction level is representing the true reaction severity.  Existing systems that are capturing both condition criticality and reaction severity may use the term "severity" to represent both.  Criticality is the worst it could be in the future (i.e. situation-agnostic) whereas severity is situation-dependent.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Estimate of the potential clinical harm, or seriousness, of a reaction to an identified substance.

# snapshot.element[].short
Code that identifies the allergy or intolerance

# snapshot.element[].definition
Code for an allergy or intolerance statement (either a positive or a negated/excluded statement).  This may be a code for a substance or pharmaceutical product that is considered to be responsible for the adverse reaction risk (e.g., "Latex"), an allergy or intolerance condition (e.g., "Latex allergy"), or a negated/excluded code for a specific substance or class (e.g., "No latex allergy") or a general or categorical negated statement (e.g.,  "No known allergy", "No known drug allergies").  Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'.  If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.

# snapshot.element[].comment
It is strongly recommended that this element be populated using a terminology, where possible. For example, some terminologies used include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNII, and ATC. Plain text should only be used if there is no appropriate terminology available. Additional details can be specified in the text.

When a substance or product code is specified for the 'code' element, the "default" semantic context is that this is a positive statement of an allergy or intolerance (depending on the value of the 'type' element, if present) condition to the specified substance/product.  In the corresponding SNOMED CT allergy model, the specified substance/product is the target (destination) of the "Causative agent" relationship.

The 'substanceExposureRisk' extension is available as a structured and more flexible alternative to the 'code' element for making positive or negative allergy or intolerance statements.  This extension provides the capability to make "no known allergy" (or "no risk of adverse reaction") statements regarding any coded substance/product (including cases when a pre-coordinated "no allergy to x" concept for that substance/product does not exist).  If the 'substanceExposureRisk' extension is present, the AllergyIntolerance.code element SHALL be omitted.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The patient who has the allergy or intolerance.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Encounter when the allergy or intolerance was asserted

# snapshot.element[].definition
The encounter when the allergy or intolerance was asserted.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
When allergy or intolerance was identified

# snapshot.element[].definition
Estimated or actual date,  date-time, or age when allergy or intolerance was identified.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Date first version of the resource instance was recorded

# snapshot.element[].definition
The recordedDate represents when this particular AllergyIntolerance record was created in the system, which is often a system-generated date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Individual who recorded the record and takes responsibility for its content.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Source of the information about the allergy

# snapshot.element[].definition
The source of the information about the allergy that is recorded.

# snapshot.element[].comment
The recorder takes responsibility for the content, but can reference the source from where they got it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].mapping[].map
IAM-14 (if patient) / IAM-18 (if practitioner)

# snapshot.element[].short
Date(/time) of last known occurrence of a reaction

# snapshot.element[].definition
Represents the date and/or time of the last known occurrence of a reaction event.

# snapshot.element[].comment
This date may be replicated by one of the Onset of Reaction dates. Where a textual representation of the date of last occurrence is required e.g. 'In Childhood, '10 years ago' the Comment element should be used.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Additional text not captured in other fields

# snapshot.element[].definition
Additional narrative about the propensity for the Adverse Reaction, not captured in other fields.

# snapshot.element[].comment
For example: including reason for flagging a seriousness of 'High Risk'; and instructions related to future exposure or administration of the substance, such as administration within an Intensive Care Unit or under corticosteroid cover. The notes should be related to an allergy or intolerance as a condition in general and not related to any particular episode of it. For episode notes and descriptions, use AllergyIntolerance.event.description and  AllergyIntolerance.event.notes.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
Adverse Reaction Events linked to exposure to substance

# snapshot.element[].definition
Details about each adverse reaction event linked to exposure to the identified substance.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Extensions that cannot be ignored even if unrecognized

# snapshot.element[].definition
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 manageable, 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).

# snapshot.element[].comment
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.

# snapshot.element[].requirements
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](http://hl7.org/fhir/R4/extensibility.html#modifierExtension).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].isModifierReason
Modifier extensions are expected to modify the meaning or interpretation of the element that contains them

# snapshot.element[].short
Specific substance or pharmaceutical product considered to be responsible for event

# snapshot.element[].definition
Identification of the specific substance (or pharmaceutical product) considered to be responsible for the Adverse Reaction event. Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'.  If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.

# snapshot.element[].comment
Coding of the specific substance (or pharmaceutical product) with a terminology capable of triggering decision support should be used wherever possible.  The 'code' element allows for the use of a specific substance or pharmaceutical product, or a group or class of substances. In the case of an allergy or intolerance to a class of substances, (for example, "penicillins"), the 'reaction.substance' element could be used to code the specific substance that was identified as having caused the reaction (for example, "amoxycillin"). Duplication of the value in the 'code' and 'reaction.substance' elements is acceptable when a specific substance has been recorded in 'code'.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Codes defining the type of the substance (including pharmaceutical products).

# snapshot.element[].short
Clinical symptoms/signs associated with the Event

# snapshot.element[].definition
Clinical symptoms and/or signs that are observed or associated with the adverse reaction event.

# snapshot.element[].comment
Manifestation can be expressed as a single word, phrase or brief description. For example: nausea, rash or no reaction. It is preferable that manifestation should be coded with a terminology, where possible. The values entered here may be used to display on an application screen as part of a list of adverse reactions, as recommended in the UK NHS CUI guidelines.  Terminologies commonly used include, but are not limited to, SNOMED CT or ICD10.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Text description about the reaction as a whole, including details of the manifestation if required.

# snapshot.element[].comment
Use the description to provide any details of a particular event of the occurred reaction such as circumstances, reaction specifics, what happened before/after. Information, related to the event, but not describing a particular care should be captured in the comment field. For example: at the age of four, the patient was given penicillin for strep throat and subsequently developed severe hives.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
Record of the date and/or time of the onset of the Reaction.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].short
mild | moderate | severe (of event as a whole)

# snapshot.element[].definition
Clinical assessment of the severity of the reaction event as a whole, potentially considering multiple different manifestations.

# snapshot.element[].comment
It is acknowledged that this assessment is very subjective. There may be some specific practice domains where objective scales have been applied. Objective scales can be included in this model as extensions.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
Clinical assessment of the severity of a reaction event as a whole, potentially considering multiple different manifestations.

# snapshot.element[].short
How the subject was exposed to the substance

# snapshot.element[].definition
Identification of the route by which the subject was exposed to the substance.

# snapshot.element[].comment
Coding of the route of exposure with a terminology should be used wherever possible.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].binding.description
A coded concept describing the route or physiological path of administration of a therapeutic agent into or onto the body of a subject.

# snapshot.element[].short
Text about event not captured in other fields

# snapshot.element[].definition
Additional text about the adverse reaction event not captured in other fields.

# snapshot.element[].comment
Use this field to record information indirectly related to a particular event and not captured in the description. For example: Clinical records are no longer available, recorded based on information provided to the patient by her mother and her mother is deceased.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())