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LOINC ® Registered Trademarks

LOINC is a registered trademark of the  Regenstrief Institute Inc.


Full LOINC and RELMA Terms of Use are  available at:

What is LOINC?

  • LOINC is a terminology that is used to standardize lab tests and other observations
  • Each LOINC record corresponds to a single test result, panel or document
    • Records identify observations such as:
    • laboratory test results
    • other diagnostic service test results
    • clinical observations and measurements
    • reports produced by clinicians
    • diagnostic services about patients
    • panels, forms and collections that define aggregations of these observations
    • orders for these entities in electronic reports and messages
  • Used ‘beneath the covers’ in electronic systems to standardize observables in lab and other clinical  domains

Why is LOINC Important?

  • LOINC provides a set of universal names and identification codes  for standardizing laboratory and clinical observables
  • Most systems have idiosyncratic names, receiving medical  systems cannot fully “understand” the information they receive  from multiple systems unless they adopt each sender’s  terminology or invest in the work to map each systems terms to  their internal code system
  • This issue could be resolved if those who need to communicate adopt LOINC codes to identify their observables


  • The HL7 CDA is a structured document specification
    • It specifies the structure and semantics of clinical documents for the  purpose of exchange
  • A CDA document can contain any type of clinical content
    • Discharge Summary, Imaging Report, Admission & Physical, Pathology Report, etc
  • LOINC is used anywhere in a CDA document when a document type needs to be identified
    • Included in the header and the body of a CDA document
  • LOINC document type Codes provide consistent semantics for  names of documents exchanged between systems
  • What is a document?
    • A collection of information
    • Contains a title, sections, sentences and other content
  • It is not a Panel
    • Panels contain enumerated, discrete element
  • Kinds of Documents:
    • Clinical Note
      • A clinical document, produced by clinicians spontaneously or in  response to a request for consultation.
    • Clinical Report
      • A clinical document, produced in response to an order for a  procedure
  • Formal Document Ontology exists in LOINC for Clinical  Notes today

LOINC Content - General

Each record contains:

  • 6 part formal name, plus LOINC numerical number with check digit
  • More than 50 columns to either further distinguish the record or  provide information about the record to help implementers. Examples  include:
    • Related Names
    • Example Units
    • Class –CHEM, HEM/BC, OBGYN, PATH etc.
    • LOINC Long Common name
    • LOINC Short name
  • Records are never deleted

What is NOT part of a LOINC Record

  • The instrument used in testing
  • Specific details about the specimen (right arm etc)
  • Priority (such as STAT)
  • Where the testing is done
  • Who did the test
  • Anything that is not an intrinsic part of the observation
  • Other data is communicated in specific places of the  electronic message

Core elements of a LOINC Record

Sample record


LOINC Content - Documents

Each record contains:

  • 6 part formal name, plus LOINC numerical number with check digit
  • Additional meta data
  • Codes are never deleted
  • Names are based on expected information content NOT document  format
    • Same LOINC for PDF, JPEG, DOC etc if information content is the  same

What is NOT part of a LOINC Document Code

  • Author
  • Location of service
  • Date of service
  • Status (e.g. signed, unsigned)
  • Security/privacy flags (e.g. protected)
  • Updates or amendments to a document
  • Other data is communicated in specific places of the electronic  message

Document Names Model

Subject Matter Domain (LOINC Method)

  • e.g. Cardiology, Pediatric Cardiology, Physical Therapy Role (LOINC Method)
  • Author training/professional classification (not subspecialty) e.g. Physician, Nurse, Case Manager, Therapist, Patient Setting (LOINC System)
  • Modest extension of Medicare/Medicade definition (not equivalent to location) e.g. Hospital, Outpatient, Emergency Department

Type of Service (LOINC Component)

  • Service or activity provided to patient e.g. Consultation, History and Physical, Discharge Summary
Kind of Document (LOINC Component)
  • General structure of the document e.g. Note, Letter, Consent


Sample record



Constructing a Document Code

Document name needs specification of a KIND OF DOCUMENT value and at least one of the other four axes.


Creating RFC’s for Documents

  • InfoRMS (Infoway Request Management System) is Infoway’s Request for Change Tool
  • Easy to use web-solution provides ability to request content additions or changes for pCLOCD
  • May also be used to monitor progress of requests
  • InfoRMS can be accessed at