Background

Interoperable deployment of SNOMED CT in support of Electronic Health Record (EHR) adverse sensitivity data (which encompasses allergy, non-allergic hypersensitivity and intolerance) is inconsistent and fails to support interoperability across SNOMED International member realms.  This arises due to confusion regarding the scope and definition of adverse sensitivity data, uncertainty regarding the reference models for defining relevant data records and inconsistency in guidance for the appropriate value sets from SNOMED CT that should populate those records.   

Several Standards Development Organizations (SDOs) such as HL7 have also provided some general guidance to assist implementers, however specific guidance in using SNOMED CT is still lacking. 

Statement of the Problem

The capture and exchange of adverse sensitivity data varies across EHRs. As an effect, much of this data is not interoperable across electronic systems. Confusion regarding the representation and definition of adverse sensitivity data within the EHR presents challenges to organizations that are trying to implement SNOMED CT for electronic data sharing. Further, this uncertainty limits the use of adverse sensitivity data for clinical decision support and longitudinal patient care records. The capture of allergy data must be clearly defined to support patient safety and a comprehensive health record.

Objective

This implementation guide is intended to accelerate consistent implementation of vocabulary with an emphasis on the use of SNOMED CT within the domain of adverse sensitivity and adverse reactions by:

• Extending previous SNOMED International work on definitions of adverse sensitivity
• Surveying and summarizing the relevant interoperability standards, 
• Advising the SNOMED International community regarding best practice deployment of allergy data within the EHR and identify the SNOMED CT refsets (value sets) that would constitute best practice for use in electronic health records.
• Addressing issues using SNOMED in day-to-day clinical practice
• Provide guidance in reconciling substances as allergens with clinical findings representing diseases and propensities as used in problem lists
• Leverage products and substances hierarchy for allergy decision support 

The benefits include:

Benefits for SNOMED International and its Members

• Members will have uniform, clear best practices for documenting adverse sensitivity.
• This work will support how adverse sensitivity information models such as in the HL7® FHIR® standard can incorporate SNOMED CT.
• Provide definitions for the community to clearly understand the terms related to adverse sensitivity such as allergy, non-allergic hypersensitivity, intolerance, etc. 
• Cost savings: Reduce investment requirements by member vendor community; consolidate NRC costs for SNOMED CT distribution of value sets.

Benefits for SNOMED CT Implementers

• Support interoperability within and between realms in a consistent way by providing clear guidance for structuring adverse sensitivity data as part of a patient’s Electronic Health Record.
• Enable consistent adoption of SNOMED CT by providing guidance on the representation of adverse sensitivity information with different levels of granularity, with and without the use of post-coordination. 

Benefits for SNOMED CT End-Users, Clinical Researchers, Health Provider Organizations, and Vendors

• Fill the knowledge gap in the community of practice by providing authoritative guidance and reference sets that can be used consistently for the representation of:
• an allergy, non-allergic hypersensitivity and intolerance 
• propensities and reactions
• the criticality of the allergic condition (i.e. the potential seriousness of a future reaction)
• the severity of a reaction 
• Provide guidance for the aggregation & analysis of reported adverse drug reactions (ADR) and sharing/interoperability of ADR reports

Scope

Our scope and approach was the following:

1. Review definitions and reference standard publications
2. Analyze relevant information models
   1. Review existing information models that are in scope, with special emphasis on HL7® FHIR® that has gained considerable momentum in recent years
   2. Create an inclusive model to harmonize the key data elements in the reviewed information models
3. Create exemplar use cases
   1. Describe the most common and important scenarios for capturing or exchanging adverse sensitivity information
   2. Illustrate how the information can be represented by using FHIR® and SNOMED CT concepts
4. Identify SNOMED CT reference sets
   1. Identify starter sets for large domains – most commonly used SNOMED CT concepts in clinical settings e.g., food allergens, adverse sensitivity reactions
   2. Identify value sets for specific data elements e.g., adverse sensitivity types, certainty, criticality, severity
5. Provide practical guidance of the use of SNOMED CT in
   1. Allergy list
   2. Problem list
   3. Clinical decision support

Audience

SNOMED CT is a comprehensive, multilingual clinical terminology that can be used to standardize and improve the quality of data related to allergies, hypersensitivities, and intolerances. This guide is targeted at the various stakeholders involved with the implementation of SNOMED CT:

• Clinicians who are interested in understanding how SNOMED CT can support the clinical needs for data collection and acquisition within the field of Allergy, Hypersensitivity and Intolerance. 
• Information managers  who are looking to learn how SNOMED CT can be integrated into health information models within the domain of Allergy, Hypersensitivity, and Intolerance to support the implementation of SNOMED CT and enhance data interoperability.
• Software developers who want to learn how to integrate SNOMED CT into software applications used in the domain of Allergy, Hypersensitivity, and Intolerance.

Attribution

This SNOMED CT Implementation guide and the underlying work has been developed by the SNOMED International Clinical Reference Group for Allergies/Hypersensitivity. The Clinical Reference Group (CRG) is composed of experts in the field of Allergies/Hypersensitivity providing input from the community of practice to on the development, maintenance and use of SNOMED CT in this specific domain. The CRG members have been instrumental in the development of this guide, providing their expertise, knowledge and experience to ensure that it is accurate, up-to-date and relevant to the needs of its intended audience. Their dedication and hard work have made this guide possible and SNOMED Internationalis is grateful for their contributions. This guide is a product of SNOMED International's ongoing commitment to improving healthcare through the use of high-quality, standardized clinical terminologies.

Guide overview

Review

This SNOMED CT Implementation guide presents the results of an analysis performed by the SNOMED International Clinical Reference Group for Allergies/Hypersensitivity between the years 2021? to 2023?. 

We welcome feedback from readers on the guide and encourage them to share their insights and experiences with us. Your comments and suggestions will help us improve the content of the guide and ensure that it is relevant and useful to those who use it. We will review any feedback received and make updates to the guide as needed. The next version of the guide is planned for 2025.

We appreciate your interest in this guide and thank you for your contributions to the improvement of healthcare through the use of high-quality, standardized clinical terminologies like SNOMED CT.