Some substances for 'non medication' related allergies/intolerances seem to be medication related

[hansdekeersmaecker]

I received a second question when checking the different codes for medication monitoring. In the list of substances, used for 'non medication' related allergies/intolerances, there appears substances that are equal to ATC codes for medication related allergies/intolerances on.

Is this the purpose? What is expected for them?

[bdc-ehealth]

@hansdekeersmaecker ,

This is a question for @mlambot .

[mlambot]

Hi,

Currently the hospitals don't use the SAMv2 or ATC codes as a dictionary for the capture of allergies. They use SNOMED CT concepts. SNOMED CT concepts of substances are used in the logical definition of a large number of SNOMED disorder and procedure concepts that will in turn be used in the problem list, in service requests, in tests and in procedure performing. Si it's important to have allergens in SNOMED CT to link with all the rest of the depending clinical data. But not all drugs are represented in SNOMED CT in the international edition. They don't represent branded products. Those have to be created in a national SNOMED extension (a project currently in evaluation at the FPS and at EU level).

The SAMv2 is supposed to contain a mapping between its codes and the corresponding SNOMED CT concepts. I don't know if this mapping is currently complete but some SAMv2 entries at least have been mapped. It is the goal that this mapping should be complete, one-to one from SNOMED CT to SAM corresponding entries to allow automatic translation into that code system so the clinicians world and the pharmacy world could both talk in their language and yet understand each other seamlessly.

So in the allergyIntolerance data model, one can currently used either the SAMv2 codes to indicate the offending agent, or a SNOMED CT codes. The SAMv2 is for when people want to indicate a branded product. Multiple codes can be technically transmitted for the same field in FHIR, with mention of the code system for each, if deemed equivalent. In the future, we could choose to deactivate the SNOMED Drug refset (value set) and code all drugs in SAM codes once there is a full SNOMED to SAM mapping and every EHR provider has a terminology server to handle the mappings. That's why it sits in a separate refset from the non-drug allergens. We are in a transition period where not all is perfectly as we'd wish. Yet we must start to walk a path to get somewhere and to figure out what still needs to be done, where and when. Anne and Bart, correct me if I'm wrong.

[hansdekeersmaecker]

Currently this is the guidance for AllergyIntolerance:

So it doesn't speek about using SNOMED CT does for medication, only ATC Codes.

So the guidance is incorrect and we must still consider them as possible medication related agents? Because this will complicate things a lot, you have multiple ways to indicate a substance. And for the example given, an ATC code is present.

[costateixeira]

I am not a clinician but my understanding is that when reporting allergies, the agent can be reported at the level of classification

On Tue, Jan 16, 2024 at 9:49 AM hansdekeersmaecker @.***> wrote:

Currently this is the guidance for AllergyIntolerance: Screenshot.2024-01-16.at.09.36.28.png (view on web) https://github.com/hl7-be/allergy/assets/104616722/39093064-2323-4292-99a5-ce0e446e75e9 So it doesn't speek about using SNOMED CT does for medication, only ATC Codes.

So the guidance is incorrect and we must still consider them as possible medication related agents? Because this will complicate things a lot, you have multiple ways to indicate a substance. And for the example given, an ATC code is present.

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[mlambot]

Can isn't must. Seems the guidance evolved on its own since I last understood it in the WG if now we must use ATC to report drug class allergies, it so I'm not competent anymore on this question @bdc-ehealth . You have to ask Anne why there is still a SNOMED Drug allergen refset if one is supposed to use only the ATC for recording drug allergies. And I would ask a question of my own as to where is the SNOMED to ATC mapping in the BE extension to make the transition to this new requirement in hospital EHRs for recovery of existing records as well as for the futur data analytics exploiting SNOMED CT concept definitions where the concept models specifies a drug substance. This is for me an unexpected change that we knew we had to face "some day" but I wasn't aware, and thus have not made our people aware, that some day had become today.

[bdc-ehealth]

The addition to the guidance was because of: https://github.com/hl7-be/allergy/issues/10

[KarlienHL7Belgium]

the non-medicinal related allergies/intolerances valueset has values linked to medication, which doesn't make sense. Anne/RIZIV will take this up with the business

[mlambot]

It made sense when we created this care set. Most CSCT Hospitals have coded allergies using SNOMED CT since 2017-2018 using precoordinated allergy to X concepts. There was from the start a 1-1 mapping provided between those precordinated concepts and the split representation type of reaction+substance because we knew we wanted to move to this spilt representation in the data model when our EHRs would be able to cope with two fields.

In 2019 the first versions of the allergy Care set was based on that pioneer work of the CSCT and took into account the early/pre-adopters of this care set, and thus provisioned to use SNOMED CT concepts to code for all, drug and non-drug allergens and later to swith registration of drug allergens to SAMv2 codes once the SAMv2 would contain a correct 1-1 mapping with SNOMED CT concepts at least at drug (substance) level. Hence the drug and non-drug refests, where the drug refset could be easily deactivated and replaced by the SAMv2 later.

Some high level - and highly used in allergy recording drug concepts - we did not know if they were represented in the SAMv2 with that "lack of detail" and we feared that if not then the users would switch to free text or not registering at all (adoption failure of the care set). Since they were absolutely essential to day to day allergy registration, we added a few essential concepts that are drugs (families) in the non-drug refset. It was a safety redundancy then and we had neither the knowledge to find out if they existed properly in the SAM nor the time to do so before the first publication of that care set. Don't forget that there was no process by then of validation by high instances of this care set, it was the first martyr. So it did go "live" to early adopters in the coalition of the willing at capture level in EHRs.

Now there was a second iteration of this care set (first for the general public but second to the early adoptes of the CoW), which has decided to move on to using the SAMv2, thus yes if you do this you should have someone who knows both SNOMED CT very well and the SAMv2 very well check what's in the SAM in the concepts that are in the non-drug refset (and actually also in the drug one) and remove all redundancies.

And a map should be orovided to early adopters to move their SNOMED CT data to SAM coding for data exchange otherwise no-one will want to be early adopter of anything in the future, as it only brings you more trouble than waiting to all specs to be cast in stone doing nothing.