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.

This records identifiers associated with this allergy/intolerance concern that are defined by business processes 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).

Record of the date and/or time of the onset The clinical status of the Allergy allergy or Intolerance. intolerance.

Individual who recorded This element is labeled as a modifier because the record status contains the codes inactive and takes responsibility for its conten. resolved that mark the AllergyIntolerance as not currently valid.

The patient who has Assertion about certainty associated with the allergy propensity, or intolerance. potential risk, of a reaction to the identified substance (including pharmaceutical product).

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.

Identification of a substance, or a class of substances, that is considered to be responsible the underlying physiological mechanism for the adverse reaction risk.

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 strongly recommended acknowledged that the substance many clinicians may not be coded with in a terminology, where possible. For example, some terminologies position to distinguish the mechanism of a particular reaction. Often the term "allergy" is used include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNI, ATC rather generically and CPT. Plain text should only may overlap with the use of "intolerance" - in practice the boundaries between these two concepts may not be used if there 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 appropriate terminology available. Additional details about tests are 100% sensitive or specific for sensitivity to a substance can 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 specified in omitted from the text. resource.

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

Decision support would typically raise alerts for 'Unconfirmed', 'Confirmed', and 'Resolved' 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 ignore is effectively redundant in that situation. When searching on category, consider the implications of AllergyIntolerance resources without a 'Refuted' reaction. In particular, 'Refuted' may category. For example, when searching on category = medication, medication allergies that don't have a category valued will not be useful returned. Refer to search for reconciliation of the Adverse Reaction List. Some implementations may choose more information on how to make this field mandatory. 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.

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

Identification of the underlying physiological mechanism 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. 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").

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 strongly recommended that many clinicians may not this element be in a position to distinguish the mechanism of populated using a particular reaction. Often the term "allergy" is terminology, where possible. For example, some terminologies used rather generically include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNI, ATC and may overlap with the use of "intolerance" - CPT. Plain text should only be used if there is no appropriate terminology available. Additional details can be specified in practice the boundaries between these two concepts may not be well-defined text.

When a substance or understood. This data element product code is included nevertheless, because many legacy systems have captured this attribute. Immunologic testing may provide supporting evidence specified for the basis 'code' element, the "default" semantic context is that this is a positive statement of an allergy or intolerance (depending on the reaction and value of the causative substance, but no tests are 100% sensitive or specific for sensitivity 'type' element, if present) condition to a particular substance. If, as is commonly the case, it specified substance/product. In the corresponding SNOMED CT allergy model, the specified substance/product is unclear whether the reaction target (destination) of the "Causative agent" relationship.

The 'substanceExposureRisk' extension is due available as a structured and more flexible alternative to an the 'code' element for making positive or negative allergy or an intolerance, then intolerance statements. This extension provides the type 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 should SHALL be omitted from omitted.

The patient who has the resource. allergy or intolerance.

Category Estimated or actual date, date-time, or age when allergy or intolerance was identified.

The date on which the identified Substance. existance of the AllergyIntolerance was first asserted or acknowledged.

Individual who recorded the record and takes responsibility for its content.

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

This data element has been included because it is currently being captured in some clinical systems. This data The recorder takes repsonsibility for the content, but can be derived from reference the Substance source from where coding systems are used, and is effectively redundant in that situation. they got it.

Represents the date and/or time of the last known occurrence 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 occurrence 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, 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.

Details about each adverse reaction event linked to exposure to the identified Substance. substance.

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 to 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 substance product that includes the identified substance. It must be clinically safe to only process the AllergyIntolerance.substance 'code' and ignore the AllergyIntolerance.event.substance. 'reaction.substance'.

Coding of the specific substance (or pharmaceutical product) with a terminology capable of triggering decision support should be used wherever possible. The substance field '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 specific substance field (for example, "penicillins"), the 'reaction.substance' element could be used for Amoxycillin. to code the specific substance that was identifed 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 the 'substance' field. AllergyIntolerance.reaction.certainty Definition Statement about the degree of clinical certainty that the specific substance was the cause of the manifestation in this reaction event. 'code'.

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.

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.

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

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.

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.