Terminology
Code Systems, Value Sets and terminologies
CodeSystems define a set of codes with meanings (also known as enumeration, terminology, classification, and/or ontology).
CodeSystems are used in ValueSet resources. In resources (Patient, Device, Observation, etc...), the Coding data type refers to CodeSystem resources by their canonical url.
The CodeSystems, Value Sets which are terminologies have the ability to exchange information and have the meaning of the information preserved upon receipt. It is here that interoperability codes such as LOINC, SNOMED CT, Roche Internal codes are critical, as they provide a common language to identify health care data. we explain the major coding systems here in detail.
LOINC - Logical Observation Identifiers Names and Codes (LOINC®) is a coding system used to describe laboratory observations and is the preferred method in HL7 to identify laboratory tests (https://www.hl7.org/fhir/observation.html#code-interop). As such, LOINC codes represent the “question” of a test or measurement (https://loinc.org/get-started/what-loinc-is/). Each LOINC code consists of several components or parts, and each part provides a specific piece of information (https://loinc.org/kb/faq/structure/).
SNOMED CT - Systematized Nomenclature of Medicine Clinical Terms, is a comprehensive, multilingual clinical healthcare terminology. Like LOINC, it's designed to support the consistent recording and exchange of clinical information, enabling interoperability between different health systems. Each SNOMED CT code represents a unique clinical concept, which can be a disease, symptom, diagnostic procedure, or other aspect of clinical care.
Roche internal codes - It is clear that using Roche internal codes reduces the degree of semantic interoperability of RDCP as it requires the distribution of data dictionaries to data receivers. However, some concepts and observations will require such a definition as external standards will not allow us to capture them. Thus, in order to reduce the use of Roche internal codes to a minimum, we recommend the following decision process that represents an order of preference:
- If a LOINC code is available for an observation, use the LOINC code
- If a SNOMED CT code (subject to the constraints mentioned above) is available for an observation, use this code
- If a combination of a LOINC code for the Observation.code field and a SNOMED CT code (subject to the constraints mentioned above) for the Observation.method field can adequately describe an observation, use this combination
- If a combination of a SNOMED CT code (subject to the constraints mentioned above) for the Observation.code field and a SNOMED CT code (subject to the constraints mentioned above) for the Observation.method field can adequately describe an observation, use this combination
- Only if none of the above is applicable, define a Roche internal code for the Observation.code field
