LOINC has just released a new accessory file containing LOINC groups. This is the first (alpha) attempt at equivalences classes for LOINC terms. We would really love to receive feedback from this community! You all represent a highly active research cohort with high likelihood of benefitting from this work so hearing from you is critical to moving forward on subsequent versions.
Please consider downloading the file (https://loinc.org/downloads/accessory-files/) and joining the discussion in our Forum (https://loinc.org/forums/forum/loinc-groups/). I’ll also monitor this forum.