LOINC

Logical Observation Identifiers Names and Codes, the Regenstrief Institute’s system for identifying laboratory and clinical observations, including imaging procedures.¹ In OIDM, LOINC’s job is exam type identification, not finding identification.

An Exam Finding List carries the exam’s LOINC code as examInfo.studyLoincCode, described as “LOINC codes: Used for exam type identification (e.g., ‘72133-2’ = CT Abdomen and Pelvis Without Contrast).”² The specification says the structure “must also have basic information (keyed by a curated list of LOINC codes) about what exam this is.”³ The lineage FHIR sample codes its DiagnosticReport the same way, with 87279-6 CT Chest for Screening.⁴

The division of labour is stated in the terminology roadmap: radiology “orderables live in the LOINC/RSNA Radiology Playbook, while findings, anatomy, and report language live in RadLex.”⁵

Synonyms and near-synonyms

• LOINC/RSNA Radiology Playbook is the radiology part of LOINC, governed separately.
• Orderable and procedure code describe what a radiology LOINC code names.
• studyLoincCode and exam_type_code are the field names that hold one.
• RadElement codes are not LOINC codes, though both can appear as index code systems.

Identifier form

Digits, a hyphen, and a check digit, for example 72133-2. The lookup tooling auto-detects the form with a pattern of one to seven digits, a hyphen, and one or two digits.

Where it is used

Exam types overview, Existing building blocks, and Exam Finding List.

Conflicts

The “curated list of LOINC codes” the specification refers to does not exist as an artifact. Exam types are documented as goals and as building blocks, not as a published catalog; see Exam types.

Footnotes

1. LOINC, Regenstrief Institute ↩

2. imaging-problem-list domain model, dev branch ↩

3. imaging-problem-list README ↩

4. Lung screening DiagnosticReport ↩

5. med-ontology-lookup product roadmap ↩