Clinical Test Data Allergies Guidance - nhsconnect/gpc-consumer-support GitHub Wiki
The clinical importance of allergy and intolerance information coupled with the variability of implementations across GP systems means that there is a need for clear guidance on the utilisation of the GP Connect AllergyIntolerance resource. Detailed implementation guidance for GP System provider population of the resource is provided in the main specification.
We have prepared a set of test records for allergies and adverse reactions to represent a wide variety of examples of how the FHIR® resource may be populated.
This page is intended to be a live document to support clinical assurance of allergies and adverse reactions in consuming systems and will be updated as new data is available or new scenarios are identified. We welcome feedback to improve the scope and detail of this information and may add further items as appropriate.
Contents
Understanding the allergy and adverse reaction records
- How are the allergy records coded?
- How should I interpret the dates for the allergies?
- How can I understand the severity, certainty or manifestation of an allergy or adverse reaction?
- Can I see how the allergy or adverse reaction was identified?
- I didn't receive any allergy records so can I take it the patient has no allergies?
Processing allergies and adverse reactions
Introduction
The recording of allergy and intolerance information in patient records is a major component of communicating the effects of external substances and compounds on patient health. The allergy and intolerance concept is broad and multidimensional:
- the causation of allergy and intolerance may be linked to specific medications or pharmaceuticals or substances (biological or chemical) in the environment
- the weight and significance that may be attached to recorded allergy and intolerance is affected by a number of factors including the certainty of the allergy, the severity of the reaction and the likelihood of occurrence
- allergies and intolerances may be linked to other clinical events, such as diagnostic tests that confirm the presence of the allergy or linked to instances of illness caused by the allergy
- allergies and intolerances may be dynamic and evolving, increasing in severity over time, recurrent or perhaps only active and observed within defined periods
- The recording and handling of allergy and intolerance information has an important role to play in patient safety, not only with regard to clinical decision making, but also in the realm of prescribing decision support, where the presence of allergy information linked to causative agents can trigger automated alerts and restrictions when prescribing
Variation in recording allergy and intolerance information
Given the complexity and depth of the allergy and intolerance domain there are significant differences and variations in the implementation of the allergy and intolerance concept across participating systems in terms of structure, terminology and the linkages between terminology and decision support. These differences limit the current interoperability of allergies and intolerances.
The GP Connect AllergyIntolerance FHIR® resource aims to improve the interoperability of allergies and intolerances through convergence towards a standardised structure and common terminology.
Roadmap and vision
The AllergyIntolerance FHIR resource has been developed to address current allergy and intolerance interoperability limitations. As such, it has been designed to enable a future state in which greater levels of allergy and intolerance interoperability are achieved by utilisation of SNOMED CT and NHS dictionary of medicines and devices (dm+d) concepts from the specified allergy and intolerance subset.
The FHIR structure and standard is only an enabler for greater drug allergy interoperability. Drug allergy interoperability is only achieved when drug allergy concepts are understood by receiving systems - that is, they trigger equivalent prescribing decision support. Therefore, the benefits will not be achieved without participating systems being able to consistently process codes from the defined causative agent subset as concepts capable of triggering prescribing decision support in receiving systems.
The system change to converge the coding of causative agents to the specified subset and make the causative agent subset consistently processable (by prescribing decision support modules across participating systems) falls outside the scope of the GP Connect programme. In the interim state it is expected that with the gradual adoption of the FHIR resource and associated terminologies, drug allergy interoperability will continue to be partial.
The AllergyIntolerance resource adopts common approaches for expressing certainty and severity, increasing interoperability of qualifiers associated with allergies and intolerances. Greater expressivity around dates (end dates, onset, occurrence) is also supported.
It is recognised that current support for the full range of severity qualifiers is limited and variable across systems, and existing support for the full range of date concepts will also be limited.
It is also recognised that there will be interim challenges in mapping existing allergy and intolerance record structures to the AllergyIntolerance resource. In some systems, allergy and intolerance information may be a post-coordinated triple of allergy code, reaction/manifestation code and causative agent code. In other systems, a single pre-coordinated code serves to describe the allergy/intolerance concept and the causative agent. In the former case, the AllergyIntolerance resource may not fully support the three coded concepts and in the latter case, there is currently no distinct identification of causative agent and reaction/manifestation.
Understanding the allergy and adverse reaction records
As described above, the GP Systems do not have a consistent way to record allergies. Details are provided in the GP Connect specification Allergies guidance page.
Some of the differences described in the specification guidance are highlighted below with associated test records to demonstrate these differences.
How are the allergy records coded?
The coding of the allergy is not limited to causative agents from the NHS dictionary of medicines and devices and its SNOMED CT equivalent codes. Other SNOMED CT concepts which represent an allergy will be present in the code element. The allergy may also have been originally captured using a terminology other than SNOMED, in which case the original code and terminology along with the SNOMED CT translation should be provided. Where the original term text differs to the current preferred term, the text element will carry the original term and the consumer is expected to present this term to its users inline with our general terminology guidance.
Allergy records could also be degraded in the source system, in which case the term text will be provided against a degrade code of 196461000000101.
GP Connect FHIR® elements
GP Connect test data examples
- Drug allergy as a product - Faverin 50mg tablets (Mylan)
- Drug allergy as disorder - Adverse reaction to erythromycin
- Drug allergy as finding - Penicillin allergy
- Degraded drug allergy - Sensitivity to Multilex action group: Antibacterials (in eye preparations)
Associated hazards
Hazard 2
How should I interpret the dates for the allergies?
The allergies resource supports three date elements but the GP systems do not support all these dates. The asserted date is a mandatory element and represents the date the patient's allergy was first know by the GP. This could differ to the date it is recorded, but if the date the allergy became known about is not explicitly captured then the GP system will return the date recorded.
The onset date is intended to carry the date of the first manifestation of the allergy. This could pre-date the asserted date and the consuming system should consider whether this, if available, would provide additional clinical meaning to the consumer.
The last occurrence date is to carry the most recent allergic reaction. This is not currently populated but the systems which have completed assurance.
Consuming systems should be able to handle partial dates for any of these date elements.
GP Connect FHIR® elements
GP Connect test data examples
- Partial date format (month/year) - Latex Allergy
- Onset and asserted dates differ - Atenolol 50mg tablets
Associated hazards
How can I understand the severity, certainty or manifestation of an allergy or adverse reaction?
The severity and manifestation of an allergy or adverse reaction may be useful clinical information, but this is not routinely recorded in GP systems and therefore cannot be relied upon in data receive via GP Connect. Systems that support capturing this information in a structured format may populate the reaction and criticality elements. Additional clinically relevant qualifiers for an allergy which are not supported by a specific FHIR element in the GP Connect allergyIntolerance profile will be populated to the note element.
GP Connect FHIR® elements
GP Connect test data examples
- Record has certainty and severity - Paracetamol 500mg capsules
- No additional detail - Penicillin allergy
Associated hazards
Can I see how the allergy or adverse reaction was identified?
GP Systems generally do not create or retain a direct association between the allergy and any information as to how the allergy was identified or verified, if such information is even known. The verificationStatus element is therefore set to a fixed value (unconfirmed), but consumers must not actively use this element or attribute any meaning to it. GP Connect does not support the evidence extension.
With further development of the GP Connect structured clinical areas, additional information may be available within the record to determine how the allergy was identified. The allergy may link to a consultation record where the allergy was first recorded, however information may be elsewhere in the record or not present at all.
GP Connect FHIR® elements
No applicable elements
GP Connect test data examples
Not applicable
Associated hazards
I didn't receive any allergy records so can I take it the patient has no allergies?
The absence of allergy records returned by GP Connect should not be taken as an assertion the patient has no known allergies. GP Connect supports the SNOMED CT concept for no known allergies. Where this has been recorded to the patient record as a positive assertion of no known allergies, then it will be returned as a coded and dated resource entry. Where an empty list or 'no known allergies' record is returned, the consumer system should consider how this relates to its use case and how to handle this information.
GP Connect FHIR® elements
Applicable elements for a no known allergies assertion.
GP Connect test data examples
Alternative test patient records must be requested to receive messages for no allergy records or no known allergies.
- No allergy records - Patient 9658218865
- No known allergies - Patient 9658218989
Associated hazards
Building a user interface
Which fields do I need to display to my users?
The fields you need to display to your users will depend on the use case that your product has been built for. Ultimately it should be the clinicians / users of the application who dictate what it is they need.
When working with your users to build your application some things to consider are:
- how can you make the information concise and easy to navigate?
- what are the key things your users need to know?
- do you need to provide any onscreen guidance to explain the information being conveyed?
- will the application have different use cases that need different views of the data?
The better you understand how the application will be used, the more appropriate your design can be.
GP Connect test data examples
All the allergy and adverse reactions in the test record should be used to evaluate your user interface. This guidance may assist with specific use cases / scenarios and related allergy or adverse reaction records, but you should utilise all the records to prove your user interface.
Associated hazards
Should I separate drug and environmental allergies?
As with all design choices, this should be a decision for your clinician users and based around your clinical use case. Some use cases may see potential benefit in focussing more on one category of allergy / adverse reaction or the other or simply to display them in separate groups. In considering this, you should be aware of the way the category definition for use in GP Connect. If the allergy is not explicitly given a category of medication or environmental in the recording system, then it MUST be assigned a category of medication if the allergy/intolerance entry interacts with prescribing decision support in the source system. Otherwise, the category of environment will be used. There are circumstances where a non-drug allergy is given a medication category and where an adverse reaction to a drug may be given an environmental category.
Should the consuming system utilise the categorisation, then it must consider how it handles such data permutations. You may choose not to make use of the category and just present the detail of the allergy or intolerance.
GP Connect FHIR® elements
GP Connect test data examples
- Environment - Aspirin-induced angio-oedema-urticaria
- Medication - Cat allergy
Associated hazards
Using search and filters?
Should I request / display resolved allergies?
GP Connect makes available resolved allergies. The concept of a resolved allergy is not supported by all systems. There is no requirement from GP Connect to request or to display resolved allergies provided their exclusion is clinically safe for the given use case.
Where a consuming system requests resolved allergies it must ensure that it maintains clear distinction between active and resolved allergies.
GP Connect FHIR® elements
A resolved allergy is identified by the GP Connect List resources (separate lists for active and resolved allergies) and by the AllergyIntolerance.clinicalStatus of 'resolved' on individual resources. Resolved allergies are intentionally unusual for GP Connect resources as they are provided as contained resources within the identifying list as opposed to being referenced resources within the bundle.
All elements are applicable for resolved allergies, but the following elements are specific to them
GP Connect test data examples
- DIAZEPAM
- Sensitivity to Multilex action group: Antimotility drugs
Associated hazards
Processing allergies and adverse reactions
Can the allergy and adverse reaction records be used with decision support tools?
User research identified the use of structured data to facilitate decision support tools as one of its key benefits. The use of structured allergy records in conjunction with decision support tools must bear in mind the allergy coding applied in GP Systems and the clinically safety risks associated with this.
Consuming systems processing allergy and adverse reaction records must degrade records which are not understood as an allergy or intolerance by its decision support system, that is the received code is not one recognised by the decision support system. The consuming system must interrupt prescribing with a disruptive warning message while degraded drug allergies are present in the patient record and inform users attempting prescribing actions of the full details of the degraded allergy before prescribing is permitted.
Any consuming systems using the allergy information for decision support must ensure there is appropriate clinical oversight of the design and testing of the system. The consumer must ensure that manual processes are in place to check the data used in decision support for an appropriate period of time to prove the system before any end to end automation may be considered for clinical assurance. See the Allergy/intolerance interoperability and clinical safety section of the GP Connect specification for full details.
GP Connect test data examples
- Transfer degrade - Latex allergy
- Transfer degrade - Sensitivity to Multilex action group: Antibacterials (in eye preparations)
Associated hazards
Hazard 2