I’m having some trouble finding information on how and when to use LOINC answer lists. I’m working on an HL7 version 2 implementation guide for immunization exchanges and we use a variety of LOINC codes as the observation ID in OBX-3. One such code is 59783-1 (status in immunization series). This code is associated with an example answer list with 4 entries. I want to make sure that it is valid to use these LA prefixed LOINC codes as the observation value in OBX-5. I’m assuming these are valid to use LOINC codes, but just wanted to make sure.
As a well, I’m interested in your best practice guidance on when a LOINC answer list should be created for a LOINC code as opposed to documenting the answers from an external code system (SNOMED for example). For example, we use a LOINC code to indicate the reason why an administered dose of vaccine is considered invalid (patient was too young at the time, intervals between doses was too short, etc). These concepts are not in SNOMED or any other external code set I’ve found, so I’m wondering if this is a good scenario to consider requesting a LOINC answer list be created. Please let me know what you think.