Analytics with SNOMED CT may be deployed on a wide range of data sources as summarized in the table below. These data sources are also known as the 'substrate' of the analytics. Please note that data which is not natively coded using SNOMED CT may be transformed using one of the techniques described in section 5 Preparing Data for Analytics. These techniques may be used to transform heterogeneous data recorded using free text or a variety of code systems into SNOMED CT, which can serve as a common reference terminology for analysis.

Table 3.3-1: Direct and indirect substrates for SNOMED CT based analytics

Analytics Substrate



Information Model

Unstructured free text document

Dictated clinical letter

Natural language

None or informal headings

Typed discharge summary letter

Structured documents with free text fields

Assessment form

Natural language

Standardized headings and fields

Discharge summary form

Structured documents with free text and post-coded classification (i.e. added by clinical coders after the clinical event

Discharge summary form with post-coded classification

Classifications (e.g. ICD)

Formal information model (typically simple)

Structured documents with non-SNOMED CT coding (e.g. proprietary, local or other coding system)

Standalone clinical application using departmental codes

Local code system, controlled vocabulary or legacy clinical terminology

Formal information model

Enterprise-wide healthcare system using local dictionaries and pick-lists

Electronic patient record using regional coding system (such as UK Primary Care systems)

Structured documents with SNOMED CT content

Cardiology report


Formal information model

GP event summary

'Big data' data store

Data warehouse

Various coding systems

Mixture of both structured and unstructured data

Data store containing a mixture of substrates

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