ECDS Diagnosis Max and Core Codes

In November 2023, ECDS Version 4 introduced an additional, approximate 58,000 diagnosis SNOMED codes called ECDS Diagnosis Max codes (also referred to as descendant or child codes). This is a significantly expanded list allowing more granularity and greater accuracy in recording diagnosis and to support new models of urgent and emergency care, such as SDEC (Same Day Emergency Care).  

Previously, only around 1,200 ECDS diagnosis codes were available, known as Core codes, which are all still valid and are included within the 58,000 Max codes. The Core codes are a ‘parent’ to the Max codes, in that all Max codes can be mapped up to one (and occasionally more than one) Core code.

This expanded list of diagnosis codes is available in the ECDS Refset MAX Specification V4.0.2 (Core codes have value ‘1000’ in the ‘Sort4’ column), where you can also find the Enhanced Technical Output Specification (ETOS) which lists the Core codes.

Users can mitigate, or map, Diagnosis Max codes to the Core codes by using the ‘ECDS MAX parent child codes’ mapping reference file, published by SUS on the 28 March 2024 (ECDS MAX parent child codes).

SNOMED changes are intended to be updated on an annual cycle. Analysts should be aware that these additions, deletions and changes to the child codes could result in changes to time series results.

Since Max codes were introduced in November 2023, we expect a gradual decrease in the coverage of Core codes, and a gradual increase in the coverage of Max codes, as provider submitters start to replace Core codes with the new Max codes.

The impact for the main ECDS A&E (Types 01 – 03) is expected to be low, although Max codes are valid for all department activity types so still need to be considered.

The increased volume of ECDS Max codes is expected to be most prevalent for the Same Day Emergency Care (SDEC) activity (Types 05 – 06).

Analysts need to consider these changes when tracking activity over time, as results may not be reflective for whole reported period.

All ECDS SNOMED-CT codes, including diagnosis codes, are validated during processing against a list maintained by Secondary Uses Service (SUS). To be valid, the diagnosis code must be present and open at the time of the ECDS activity, whereby the ECDS arrival date is checked against the diagnosis start / end dates that are also maintained on the SUS list.

Any diagnosis codes that are not valid will be blanked out in the published ECDS data product.

It is not possible to identify whether the diagnosis code is Max or Core from the Data Product itself, though this information is available

Automated mapping from Max to the Core codes has been developed within processing for the new and improved ECDS Data Product in DAE. This gives users the option to report on either Core diagnoses only (DIAGNOSIS_CODE_CORE mapped back from the Max), or both Core and Max diagnoses (DIAGNOSIS_CODE as submitted) to suit individual analytical requirements.

Reporting on the mapped Core codes enables analysts to retain continuity prior to Max being introduced for time series analysis and remove the need to consider the extended list of Max codes. The Max codes give granularity and greater accuracy in reported patient diagnoses, especially for reporting on SDEC.

This mapping will not be available in within RDS SQL which will retain both Core and Max codes as submitted.