Many countries support a curated, nationally-approved list of LOINC codes for use in their jurisdiction. To support users in these countries, we allow a flexible import mechanism whereby users can subset their searches only to that approved list. Rather than search the whole 80,000+ LOINC database, their searches within RELMA are limited to only what they need.
Or, maybe you have a different use case but still want to narrow your searches to a particular set of terms.
Now, with custom subsets, you can upload and define your own list of LOINC codes for use within RELMA. Each subset you create can be used as a custom filter to limit your search results.