Risk of harmful or undesirable, physiological response which is unique to an individual and associated with exposure to a substance.

To record a clinical assessment of a propensity, or potential risk to an individual, of an adverse reaction upon future exposure to the specified substance, or class of substance.

Substances include, but are not limited to: a therapeutic substance administered correctly at an appropriate dosage for the individual; food; material derived from plants or animals; or venom from insect stings.

The logical id of the resource, as used in the url for the resoure. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation. Bundles always have an id, though it is usually a generated UUID.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content may not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element as much as possible.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource

Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A human-readable narrative that contains a summary of the resource, and may be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again.

An Extension

• unordered
• Open
• discriminators: url

The estimated patient age at which the allergy or intolerance resolved. Should be specified only if the status is resolved.

A code capturing the explanation of why the allergy or intolerance has been refuted. Should be specified only if the status is refuted.

May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

This records identifiers associated with this allergy/intolerance concern that are defined by business processed and/ or used to refer to it when a direct URL reference to the resource itself is not appropriate (e.g. in CDA documents, or in written / printed documentation).

Date when the sensitivity was recorded.

Indicates who has responsibility for the record.

The patient who has the allergy or intolerance.

The source of the information about the allergy that is recorded.

The recorder takes repsonsibility for the content, but can reference the source from where they got it.

Identification of a substance, or a class of substances, that is considered to be responsible for the Adverse reaction risk.

It is strongly recommended that Substance be coded with a terminology, where possible. For example, some terminologies used include RxNorm, Snomed CT, DM+D, NDFRT, ICD-9, IDC-10, UNI, ATC and CPT. Plain text should only be used if there is no appropriate terminology available.

Assertion about certainty associated with the propensity, or potential risk, of a reaction to the identified Substance.

Decision support would typically raise alerts for 'Unconfirmed', 'Confirmed', and 'Resolved' and ignore a 'Refuted' reaction. In particular, 'Refuted' may be useful for reconciliation of the Adverse Reaction List. Some implementations may choose to make this field mandatory.

Estimate of the potential clinical harm, or seriousness, of the reaction to the identified Substance.

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).

Identification of the underlying physiological mechanism for the Reaction Risk.

Immune-mediated responses have been traditionally regarded as an indicator for escalation of significant future risk. Contemporary knowledge suggests that some reactions previously thought to be immune and non-immune and still carry life threatening risk.

It is acknowledged that many clinicians may not be in a position to distinguish the mechanism of a particular reaction. This data element is included nevertheless because many legacy systems have captured this attribute.

Immunological testing may provide supporting evidence for the basis and causative substance , but no tests are 100% sensitive or specific for a sensitivity.

Category of the identified Substance.

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.

Represents the date and/or time of the last known occurence of a reaction event.

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

Additional narrative about the propensity for the Adverse Reaction, not captured in other fields.

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.

Details about each Adverse Reaction Event linked to exposure to the identified Substance.

unique id for the element within a resource (for internal references).

May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Identification of the specific substance considered to be responsible for the Adverse Reaction event. Note: the substance for a specific reaction may be different to the substance identified as the cause of the risk, but must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite substance that includes the identified substance. It must be clinically safe to only process the AllergyIntolerance.substance and ignore the AllergyIntolerance.event.substance.

Coding of the Specific Substance with a terminology capable of triggering decision support should be used wherever possible. The Substance field allows for the use of a specific substance or a group or class of substances, for example "Penicillins". The specific Substance field could be used for Amoxycillin. Duplication is acceptable when a specific substance has been recorded in the 'Substance' field.

Statement about the degree of clinical certainty that the Specific Substance was the cause of the Manifestation in this reaction event.

Clinical symptoms and/or signs that are observed or associated with the Adverse Reaction Event.

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.

Text description about the Reaction as a whole, including details of the manifestation if required.

Record of the date and/or time of the onset of the Reaction.

The amount of time that the Adverse Reaction persisted.

Clinical assessment of the severity of the reaction event as a whole, potentially considering multiple different manifestations.

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

Identification of the route by which the subject was exposed to the substance.

Coding of the Route of Exposure with a terminology should be used wherever possible.

Additional text about the Adverse Reaction event not captured in other fields.