# Specialising value set items?

**Category:** [Clinical](https://discourse.openehr.org/c/clinical/5)
**Created:** 2020-09-10 11:00 UTC
**Views:** 773
**Replies:** 4
**URL:** https://discourse.openehr.org/t/specialising-value-set-items/970

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## Post #1 by @siljelb

I'm working on a specialisation of an archetype. The parent archetype has a DV_CODED_TEXT element with internal codes, with SNOMED CT codes bound to each internal code. The specialisation slightly narrows down the definition of each internal code, which I would like to reflect by specialising each code in terms of textual description and which SNOMED CT code is used. AD isn't letting me do this. Is this a tooling issue or a specifications issue?

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## Post #2 by @thomas.beale

[quote="siljelb, post:1, topic:970"]
The specialisation slightly narrows down the definition of each internal code
[/quote]

Hi Silje,

Not sure what this bit means - the meaning of an already-defined code in an archetype cannot be redefined, just like a code in SNOMED or ICD. Or do you mean that the codes have been specialised, e.g. at12 -> at12.1 etc? If so, the latter are distinct, semantically specialised codes, in the same sense that the code for 'lymphoma' is a specialised child of 'cancer' (or malignant neoplasm, or whatever it is), and you should be able to define them normally.

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## Post #3 by @siljelb

[quote="thomas.beale, post:2, topic:970"]
Or do you mean that the codes have been specialised, e.g. at12 -> at12.1 etc?
[/quote]

I mean that this is what I'm trying to do, but the tool won't let me. For example, I want to specialise the finding code "Heart beat irregular" to "Pulse irregular".

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## Post #4 by @thomas.beale

Aha! So it's a tool problem... [this is the part of the spec](https://specifications.openehr.org/releases/AM/latest/ADL2.html#_object_redefinition) that talks about redefining codes - but it might depend on you having created the relevant specialised nodes first? I guess you did that?

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## Post #5 by @siljelb

[quote="thomas.beale, post:4, topic:970"]
but it might depend on you having created the relevant specialised nodes first?
[/quote]

I'm unable to find a way to explicitly specialise each code, only the data elements. Sounds like a tooling issue then?

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**Canonical:** https://discourse.openehr.org/t/specialising-value-set-items/970
**Original content:** https://discourse.openehr.org/t/specialising-value-set-items/970