The specification for the Result Observation template currently states that if Observation/value is a CD (xsi:type="CD") the value SHOULD be SNOMED-CT. However, this doesn't quite align with LOINC in some cases.

I recommend we change this template to state that if Observation/code is a LOINC then the value SHOULD be taken from the associated LOINC Answer List. Many of those Answer Lists contain a mix of codes, only some of which are SNOMED CT. For example, see 5782-8. Also, we should provide some guidance as to which code system OID to use for LOINC Answers that aren't SNOMED CT. I'm not sure whether the example below is really correct because the OID is for LOINC Answer List LL891-3 rather than for a code system per se.

<value xsi:type="CD" code="LA12831-6" displayName="Pyrophosphate crystals" codeSystem="1.3.6.1.4.1.12009.10.1.3310" codeSystemName="LL891-3" />