For several years, LOINC has published a set of common lab orders. These rankings are published within the primary LOINC table as COMMON_ORDER_RANK. An accessory file collecting these values is also made available within the LOINC distribution as LoincUniversalLabOrdersValueSet.csv.
Thanks to a request from the community, we have published this value set to the LOINC Terminology Service using HL7® FHIR®. Omission of this set was an oversight on our part.
ValueSet definition: https://fhir.loinc.org/ValueSet/?url=http://loinc.org/vs/top-lab-orders
ValueSet expansion: https://fhir.loinc.org/ValueSet/$expand?url=http://loinc.org/vs/top-lab-orders
Our TS documentation has been updated to reference this new ValueSet. You may also read more about the set of laboratory order codes.