Retired RxNorm codes in PartRelatedCodeMapping.csv

General
1

There are 3 RxNorm codes in column “ExtCodeId” (PartRelatedCodeMapping.csv) which seem to be retired (inactive): 70618, 114189, 662411.

Could you please confirm if the mappings between LOINC Parts and the 3 RxNorm codes are correct? And if the RxNorm codes are no longer active, are the mappings still relevant?

2

Hi Ali,

There are actually 4 mappings to rxnorm that may be considered invalid or inactive for different reasons:

  • LP14319-5 | Penicillin | is mapped to archived RxNorm code 70618 | Penicillin | . This is likely due to “penicillin” being considered a class of compounds and not a single medication. This is easy to see in how it was mapped for the LOINC/SNOMED collaboration which mapped the property to 373270004 |Substance with penicillin structure and antibacterial mechanism of action (substance)|. RxNorm doesn’t contain classes and would require a complex map to map to more than one actual medication. (e.g. Penicillin V, Penicillin G, etc.)

  • LP15505-8 |Cobalamins| is mapped to archived RxNorm code 42604 |Cobalamins|. The LOINC/SNOMED cooperative mapped this to 304111003 |Cobalamin (substance)|. RxNorm does not have a concept for cobalamin, however, the mapping could be reviewed to determine if 11248 | Vitamin B12| is a close enough approximation that the part mapping could be updated.

  • LP14565-3 | Opiates | is mapped to archived RxNorm code 114189 | Opiates |. The LOINC/SNOMED cooperative mapped this to 404642006 |Substance with opioid receptor agonist mechanism of action (substance)| which represents a class of medications and not a single medication. RxNorm wouldn’t be appropriate as there wouldn’t be a class code available. I would suggest requesting that this mapping to RxNorm be removed from the file.

  • LP15747-6 | Gentamicin | is mapped to archived RxNorm code 662411 | Gentamicins |. This mapping should be reviewed and potentially updated to 1596450 | gentamicin | in the LOINC external part mapping.

This analysis was completed using LOINC Version 2.78 and Rxnorm September 2024 monthly release.

I hope this helps.
Thanks
John

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3

Hi John,
I appreciate the analysis you provided. Yes, I agree with you, these mappings should be revisited and reconfigured. I will circle back on this question.
Thank you
Eza

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