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Concepts

Fatunmbi Daniel edited this page Jul 19, 2026 · 1 revision

Concepts

The vocabulary this client speaks, and why each idea matters. Read this once and the method names in Guides and API-Reference read themselves.

Concept

A single clinical idea: a drug, a lab test, a diagnosis. Each concept has a stable numeric conceptId that stays the same no matter which coding system originally named it.

Why it matters: concepts are the anchor everything else hangs off. Once you hold a conceptId, every other namespace (interactions, mappings, reference ranges) takes it as input.

Vocabulary

A source coding system such as SNOMED CT, RxNorm, or LOINC. The same idea often has a different code in each.

Why it matters: HOLON normalizes across vocabularies so you work with one concept instead of many codes. When you already hold a raw code from one system, concepts.getByCode(code, vocabulary) resolves it to the concept.

Domain

What kind of thing a concept is: a Drug, a Measurement, a Condition.

Why it matters: domains let you narrow a search to the category you mean. A search for a term that names both a drug and a condition returns fewer, more relevant hits once you pass a domain.

Mapping and translation

A mapping links the same idea across two vocabularies. Translation is the act of moving a code from one vocabulary into its equivalent in another.

Why it matters: translating a RxNorm code into its SNOMED equivalent is how you move a patient's data between systems that speak different codes. See the mappings namespace in Guides.

Reference range

The normal range for a lab test, narrowed by age and sex, so a value can be read as high, low, or in range for that specific patient.

Why it matters: a raw lab number means little without context. The same value can be normal for one demographic and abnormal for another. Reference ranges give you the boundary to compare against.

Drug interaction

A known, clinically significant effect between two drugs.

Why it matters: the interactions API screens a pair or a whole medication list, so you catch a risky combination before it reaches a patient.

Phenotype similarity

A score for how alike two sets of phenotype terms are.

Why it matters: it is how you compare patients, or match a presentation to a candidate condition, when exact codes will not line up. You get a similarity signal where a code-for-code match would return nothing.

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