Issue Fetching Normative Answer Lists via CodeSystem/$lookup API

General
1

Dear team,

My goal is to fetch all LOINC-to-LOINC Answer List mappings, as indicated in the LoincAnswerLinkList.csv file via FHIR API

I’ve observed the following behavior:

  • For LOINC codes where the AnswerListLinkType is “EXAMPLE” or “PREFERRED”, the associated answer list information is successfully returned in the API response. For example, fhir.loinc.org/CodeSystem/$lookup?system=http://loinc.org&code=100019-9 (which has an EXAMPLE answer list) works as expected.
  • However, for codes that have an AnswerListLinkType of “Normative” in the LoincAnswerLinkList.csv file, the CodeSystem/$lookup API does not seem to return the corresponding normative answer list information. For example, for LOINC code 100002-5 (which is listed as having a Normative answer list in the CSV), the API response does not include this answer list.

My question is:
How can I reliably fetch the LL-type codes (LOINC Answer List IDs) and their associated answers when their AnswerListLinkType is “Normative” using the fhir.loinc.org API?