dm+d virtual therapeutic moietys (VTMs) and virtual medicinal products (VMPs), where an equivalent exists, use SNOMED CT International Edition (IE) concept identifiers as their unique ID. Recent changes to the IE model and editorial policy mean that the IE definition of VTM and the dm+d definition no longer align.
In dm+d, the VTM groups together VMPs that have only that VTM - for example, paracetamol and codeine VMPs are not children of paracetamol VTM.
The IE definition of these existing concepts (that dm+d is linked to) has changed to ‘contains some’. That is, the VMPs below a VTM have this VTM and possibly others too, whilst concurrently introducing new ‘contains only’ concepts. Therefore, some dm+d VTMs are now linked to incorrect IE concepts.
This will have implications on implementations using VTM/VMP inheritance and links to support - for example, allergy.
All VTMs using IE codes will be changed to the correct ‘contains only’ VTM where applicable. Where a new IE ‘contains only’ VTM does not exist, a UK extension ID will be assigned.
What to consider
- Do you use/map to VTM concepts?
- If your system supplier manages your dm+d data, ask them how they plan to make these changes in their systems and what impact there may be to end users
- How will dm+d updates be managed where you have systems that integrate with each other?
- If the trust manages dm+d data, what will be the process for taking and handling the code changes in dm+d updates? Do you use ‘current’ and ‘previous’ VTM IDs?
The availability of dm+d ‘historic codes’ will support you with these changes.