Overview

Any SNOMED CT subsets, used to code COVID-19 data, should be designed based on the context in which they will be used, and other specific usage requirements.

To make the process of planning and designing your SNOMED CT subsets more efficient and internationally consistent, we recommend the following three steps.

These three steps are explained in more detail below.

Step 1 - Identify Data Elements

The first step is to identify the data elements that may require SNOMED CT coding. These data elements may already be defined in national reporting requirements ^1 2, or you may be developing a new information model (or data set) for a new purpose. Your requirements for coded content will depend on your specific use case and the data items in your information model. In addition, different countries, regions, and hospitals may apply different clinical techniques or practices, which can also result in differing coding requirements. Therefore, deciding which subsets to implement requires clarification of the scope of content needed, by answering questions such as:

• What will your SNOMED CT subsets be used for?
  • Will they be used to capture new data in a clinical information system to support frontline service delivery?
  • Will they be used for disease surveillance?
  • Will they be used to integrate data from various sources?
  • Will they be used for international collaboration?
  • Will they be used for retrospective analysis of data?
• Which data elements are required for your use case?
  • What coded data needs to be collected to support clinical care?
  • What coded data needs to be collected to provide disease surveillance?
  • What coded data needs to be shared between or integrated from different sources?
  • What coded data is required for international collaboration?
  • What coded data may be needed for retrospective data analysis?
• What existing subsets are available for the data elements of interest?
  • Where these subsets designed based on the same or compatible requirements?

Answering these questions will help in understanding which of the existing subsets are relevant for your context. It may also help to identify potential content gaps in the subsets, or extraneous concepts which are not required for your specific scenario. Please note that the questions above are provided for inspiration only. Additional questions specific to your use case are likely to be needed.

Step 2 - Download Subsets

The second step is to download any available existing subsets that are associated with your required data elements.

The international SNOMED CT COVID-19 subsets are made available via SNOMED International's Reference set and translation tool - https://refset.ihtsdotools.org/.

These subsets have been placed in the 'COVID-19 subsets' project and are named according to the naming convention presented below. 

Subset Naming Convention

The international subsets provided by SNOMED International have been named using the following convention.

The table below shows some examples of subsets named using this convention. 

Subset Categories

The international SNOMED CT subsets have been organized into a number of categories, based on groupings of data elements that are likely to be recorded together. The six categories identified are:

• Provider and Facility Details (PRF)

• Patient Demographics (PAT)

• Clinical Assessment (ASS)

• Tests and Investigations (INV)

• Prevention, Treatment, and Education (PTE)

• Other Covid-19 Related Data (OCD)

Please follow the links above for information on the specific subsets within each category.

Subset Types

Some of the international subsets have been developed intensionally, while others have been developed extensionally. Please refer to the Practical Guide to Reference Sets, section 2.1.1. Subset Definitions for information on the difference between intensionally and extensionally defined subsets. 

For each extensionally-defined subset, where the members have subtypes, we provide two versions:

• One version which includes only the listed members
• One version which includes the members listed and the subtypes of each of these members. This version supports the collection of more specific values where these are available.

Step 3 - Review and Adapt

The third step is to carefully review each international subset, and adapt it to meet your specific requirements. The subsets provided represent a collection of concepts that have been contributed from a range of SNOMED International Members. It is therefore important to review each subset member to:

1. Identify any concepts that are not required for your use case;
2. Identify any concepts missing from the subset that may be required for your specific use case.

Please ensure that any concepts included in your subsets are available in the SNOMED CT Edition that is implemented in your system. This may involve:

1. Reviewing the effective time of each international concept (shown in the subset tables) to ensure that it is less than or equal to the International Version used in your local system.
2. Checking that any extension concepts included are published within the SNOMED CT edition you are using.

Unpublished Content

Please note that the subsets in this guide may include unpublished content (e.g. planned for the July 2020 International Edition). This content should not be used until it has been officially published. Concepts that are currently planned to be published in the July 2020 International Edition have been included in this guide to assist with planning.

Extension Content

In response to an immediate need for COVID-19-specific concepts, various Member countries have developed concepts within their national SNOMED CT Extensions. These extension concepts are documented in this guide and may be used as an inspiration to other Members. Please note, however, that extension concepts should only be used when the module in which they are published is included in the implemented SNOMED CT Edition. SNOMED CT extension concepts are not included in the subsets available via the Reference Set tool.

Feedback

We welcome comments, feedback, and suggestions.

Footnotes