Every test/terminology in LOINC has 17 attributes. Wiki lists the following 6 six fields as unique specification of each identified single test, observation, or measurement-
Component
Property
Time aspect
System
Scale
Method
Every test has a unique code/ID in the format - nnnnn-n, short name and long name.
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Use this link to look up LOINC terminologies.
https://www.hl7.org/implement/standards/FHIR-Develop/loinc.html