LOINC Version 2.67 and RELMA Version 7.0 are now available

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LOINC 2.77
Released 2024-02-27

RELMA 7.10
Released 2024-02-27


We are excited to announce that LOINC version 2.67 and RELMA version 7.0 are now available! This release contains lots of new content and feature updates. Here is what we'll cover in the announcement:

    1. LOINC content highlights
      1. New content
      2. Content edits
    2. Display Names are now production status
    3. What's new with the LOINC FHIR Terminology Services API
      1. Updated LOINC content
      2. New properties
      3. ConceptMap enhancements
      4. Questionnaires
      5. Updated definition of LOINC as a code system resource
      6. Updated information on loinc.org/fhir
    4. Official release of the new details pages and links to Lab Tests Online
    5. RELMA version 7.0
      1. Search using web-based SOLR search engine
      2. New details pages available through RELMA
    6. LOINC Linguistic Variant Updates
    7. Update to the LOINC Versioning policy
    8. New LOINC Document Ontology OWL File
    9. Key changes to existing LOINC release artifacts
      1. LOINC License
      2. LOINC Display Name File
      3. LOINC Part File
      4. LOINC/IEEE Medical Device Code Mapping File
    10. Your feedback is needed for promoting these LOINC artifacts!
      1. LOINC Change Snapshot File
      2. LOINC Multiaxial Hierarchy File
      3. LOINC Part File
      4. LOINC Group File
      5. LOINC Consumer Name File
    11. Changes to the public LOINC data files in this release
      1. LOINC Table
      2. LOINC Linguistic Variant File
    12. Notice of changes to the public LOINC data files for the December 2020 Release
      1. LOINC Table

Read on for the full details.

Highlights from the latest LOINC release

This section describes the most important changes included in the current LOINC release.

As always, see the documentation included with each release artifact for more information.

92369 total LOINC terms!

That means that 8 character codes (6 digits, a dash, and a check digit) will be arriving before you know it. Start preparing now!

New content highlights

523 Laboratory + 238 Clinical + 220 Survey = 981 new terms

Individual terms include:

  • Laboratory
    • Approximately 90 new microbiology terms
    • Nearly 80 new chemistry tests
    • Approximately 50 new terms in each of the DRUG/TOX and CHAL classes
    • Over 60 new molecular pathology terms
    • Plus new terms in blood bank, serology, allergy, coagulation, cell markers and more
  • Clinical
    • About 90 new terms in cardiology and radiology
    • More than 50 new clinical document terms
    • Approximately 40 new terms for various history and physical concepts
    • Plus terms related to home accessibility, vaccines, Ob/Gyn and more

New clinical and survey panels include:

  • Columbia - Suicide Severity Rating Scales (C-SSRS) and screener 93245-9, 93373-9, 93485-1
  • Quality of Working Life Questionnaire for Cancer Survivors 93088-3
  • WellRx Questionnaire - revised 93667-4
  • Revised Prenatal Distress Questionnaire - Concurrent Self-Administered Version 93083-4
  • Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-Be Difficulties in Pregnancy form 93084-2
  • Polysomnography panel 90568-7
  • HEDIS 2020 Value Set updates 94137-7
  • Outcome and assessment information set (OASIS) form - version D1 93055-2
  • Inpatient Rehabilitation Facility - Patient Assessment Instrument - version 4.0 93128-7
  • Long-Term Care Hospital (LTCH) Continuity Assessment Record and Evaluation (CARE) Data Set (LCDS) - version 5.00 93223-6

Edits to existing terms

Approximately 2600 terms were edited for this release

Changes based on internal review or as part of an ongoing project:

  • Corrected scientific name for cantaloupe allergy terms
  • Updated approximately 150 cardiology procedure terms for consistency in modeling the Component, System, and Method
  • Reclassified terms into ADMIN and MOLPATH.PHARMG Classes
  • Updated approximately 50 radiology terms for consistency in Component modeling
  • Added a new CHNG_TYP of PANEL in order for users to determine which panels have been updated. At this time, panel updates that are flagged for this CHNG_TYP are limited to changes in the child elements or changes in the conditionality of one or more child elements in the panel or a sub-panel contained in the panel.

Changes based on community input:

  • Corrected Long Common Name and Display Name for terms with Cucumis melo spp. as the Component to include "Melon" rather than "Honeydew melon", because cucumis melo is the generic name for melon
  • Updated multiple Display Names for consistency
  • Added alternate formulas to Specific airway resistance by Plethysmograph body box term 91980-3
  • Added tall man lettering to Parts that were overlooked in the 2.66 release
  • Moved 89260-4 Area of wound from 72292-6 Wound exudate panel to 72287-6 Wound size panel
  • Corrected spelling of Teicholz to Teichholz in two Method Parts
  • Updated the OrderObs value for several terms from Order or Observation to Both
  • Added new disorders to several newborn screening Answer lists
  • Added new answer strings to several Cardiology Answer lists
  • Corrected the System for ABO and Rh group type term 881-3 from Ser/Plas^BPU to Bld^BPU
  • Added Plas to the existing Ser System for several terms
  • Fixed a bug in the Multiaxial hierarchy that was causing all of the Radiology terms to appear in the "NotYetCategorized" node
  • Corrected mu character to "u" in several example unit values
  • Added "GRCh38" as an Answer string to the Human reference sequence assembly version Answer list
  • Updated several panels by adding additional child elements and making the required/optional/conditional values less restrictive
  • Updated the Component Aquaporin 4 receptor to Aquaporin 4 water channel per current scientific nomenclature


We have been assessing the best way to provide users with information about updates to LOINC terms (and Parts). We have published an Updates File for many years, which includes information about term edits in both .mdb and .csv formats, as well as the Difference Report, which is a PDF report that allows users to quickly scan what edits were made to the major Parts of a term. In June 2019, we published the ChangeSnapshot artifact for the first time; this file currently contains any Status changes for LOINC terms and Parts in separate .csv files, with one row per term or Part; however, no other term- or Part-level changes are included in this file. We welcome user input on the format you would find most useful, whether it is a single artifact with one row per field-level change, or multiple artifacts for different types of changes.

Display Names are now production status

After two years of review and refinement, and we are happy to announce that Display names have been promoted to production status and included in the main LOINC table!

Even though they have been promoted, we still welcome feedback if you find any errors or inconsistencies.

What's new with the LOINC FHIR Terminology Services API

Updated LOINC content available through the API

During our release process we have updated our FHIR terminology server with the latest content. The server currently supports CodeSystem, ValueSet, ConceptMap, and Questionnaire resources.

New Properties

Parent/Child relationships based on the Multiaxial Hierarchy

LOINC terms and Parts have relationships via the LOINC Multiaxial hierarchy. These relationships can be found by using the $lookup operation in conjunction with the newly implemented parent and child properties, which are defined by FHIR.

Based on the hierarchy, LOINC Parts have a single parent and can have one or more children. Because LOINC terms only exist at the leaf-level in the hierarchy, they will have a parent but no children.

In the future we anticipate enhancing our implementation to enable ancestor and descendant queries.

Display Names

We added a new DisplayName property so that you can access the newly-promoted names using our FHIR API. The DisplayName property is not yet available.

ConceptMap enhancements

With this release, we have updated all existing and new concept maps to be bidirectional, so that you can find all of the external code system concepts that are mapped to a particular LOINC term or Part, as well as all of the LOINC terms or Parts mapped to an external code.

We have added the following new maps:

  • LOINC terms -- PhenX concepts
  • LOINC terms -- CMS Long-term Post-acute care (LT-PAC) assessment concepts
  • LOINC Parts -- NCBI ClinVar concepts
  • LOINC Parts -- ChEBI concepts
  • LOINC Parts -- NCBI Gene concepts
  • LOINC Parts -- NCBI Taxonomy concepts

Each individual map has an equivalence value that indicates whether the source and target concepts are equivalent or whether one is wider or narrower in meaning than the other. Note that FHIR defines the equivalence as going from the target concept to the source, so if the equivalence value is "narrower", that means the target concept is more specific than the source concept.


FHIR's questionnaire resource provides a way to represent a set of questions in a structured format along with associated information such as answer lists, instructions, and skip logic. The Argonaut questionnaire profile is a specific implementation of the questionnaire resource, and we have chosen this profile for our first deployment of LOINC panels as FHIR questionnaires.

Our current deployment renders the LOINC panels as they are currently represented in the database, including bindings between LOINC terms and Answer lists and any codes or scores contain in each list. In the future we anticipate enhancing the content so that we can add more features, such as computable skip logic.

Updated definition of LOINC as a code system resource

We have updated the canonical definition of LOINC as a CodeSystem resource to include the latest enhancements. LOINC's CodeSystem definition is available for download at https://loinc.org/fhir/loinc.xml.


Interested in learning more? You can find more details and try out examples for each resource on loinc.org/fhir. We have also added information about the new resources and a short section of definitions to help get you started.

Official release of the new details pages and links to Lab Tests Online

Some of you may have noticed that we rolled out a brand new set of details pages a few months ago, but this is our first public release in which all of the pages have a fresh new look.

These awesome new pages are available for:

  • LOINC terms
  • LOINC Parts
  • LOINC Answer lists
  • LOINC Groups
  • LOINC Community mappings

We are also excited to announce the inclusion of links to the most frequently accessed Lab Tests Online (LTO) pages in the Reference Information section of the corresponding LOINC details pages. For example, LOINC 1971-1 Bilirubin.indirect [Mass/volume] in Serum or Plasma is linked to the LTO Bilirubin page, and the LTO Bilirubin page is linked to 1971-1 as well as other LOINC terms related to bilirubin. This work was done as part of our collaboration with LTO and we look forward to continuing our work together and expanding the scope of the content that is linked.

RELMA version 7.0

Search using web-based SOLR search engine

This release introduces a major change in how RELMA executes searches. By default, RELMA will now use a server based search engine that runs in the LOINC cloud environment. The search engine is our implementation of the extremely popular SOLR search engine. Behind the scenes, SOLR still uses the same Lucene technology that we have relied on for many years, so the search syntax and results are the same.

TIP You can find the same detailed search syntax instructions that are available in RELMA in the online search application by going to the Help menu and selecting Query Syntax.

New details pages available through RELMA

Another new feature we are excited to announce is the new, updated Details pages that RELMA will display in your default web browser when you use the new SOLR search engine.


One major difference in functionality with the change to SOLR is that you are required to log in to run a search. If you do not log in when you start the program, you will prompted when you click the search button.

For this release, we have still retained the old functionality with the option of running searches locally. If you do not want to use the enhanced SOLR search engine, you can switch to the old Lucene search engine on the User Preferences screen. Be aware, this option will be eliminated in a future version of RELMA. Also, the new Details pages are only available online, so switching to the local Lucene option forces RELMA to create the Details pages locally in the old format.


Returning extremely large numbers of search results can result in poor performance. A new setting on the search engine tab of the User Preferences screen allows users to control the maximum number of results
returned from a search.

You will receive an error if you manually add a new local term and then delete a local term in the same session. As a work around, after you add a local term close and restart the program before manually deleting a local term.

The RELMA Export full panel structure function generates an Excel spreadsheet that represents a panel term and all its children. However, certain panel terms such as 50586-7 Glucose tolerance 3 hours panel - Serum or Plasma do not have an explicit list of child terms. Attempting to export these terms will result is an unexpected error. This issue should cause no harm and you can safely continue using the application. We will fix this issue in a future release.

LOINC Linguistic Updates

The global community of LOINC users continues to help produce a wonderful collection of translations. These linguistic variants (we support multiple translations of the same language) are available in RELMA, the online search.loinc.org application, and in the LOINC Linguistic Variants File.

Updated Linguistic Variants in this release:

  • nl_NL_22 - Dutch (NETHERLANDS)
  • fr_CA_8 - French (CANADA)
  • de_AT_24 - German (AUSTRIA)
  • zh_CN_5 - Chinese (CHINA)

Users should note that we intend to retire the translations produced by CUMUL in a future release. That translation effort was suspended many years ago and more comprehensive translations into French, German, and Italian have been produced by others.

Update to the LOINC Versioning policy

We have made a small change to the LOINC Versioning policy. Prior to the December 2019 release, the preproduction label was appended with an additional dot and number, such as Alpha.2 or Beta.1. As this additional designation did not have a clear purpose, we decided to remove the extra digit and have implemented the change for this release.

NEW LOINC Document Ontology OWL File

We are excited to announce our first OWL artifact. With this release, we have published the inaugural version of the Document Ontology file in OWL format. In general, knowledge expressed in OWL format is computer-readable and can represent rich knowledge about resources (such as LOINC parts and LOINC terms) and the relationships between them, which is possible to query for building visual representations and making inferences.

The Document Ontology OWL file is provided as a separate artifact with its own set of Release notes and Readme file.

We are requesting user feedback on the design and format of this file, as well as information about potential use cases and how users are planning to implement the file.

Key changes to existing LOINC release artifacts

LOINC License

The license accompanying this release has been updated to Version 4.0 in accordance with the LOINC Versioning Policy, because we added references to our new LOINC Document Ontology OWL File and removed references to the LOINC Display Name File,

LOINC Display Name File

This file has been discontinued because the Display Names have been promoted to production status and are now included in a new DisplayName column in the main LOINC table.

LOINC Part File

We have incremented this file to Version 4.0 due to the following structural change: the MapType field in the PartRelatedCodeMapping file was renamed to Equivalence according to the HL7 FHIR ConceptMap model.

The major content changes for this release include:

  • Part mappings to four additional external coding systems (ChEBI, NCBI taxonomy, NCBI gene, and NCBI clinvar).
  • Addition of category type linkages between LOINC Parts and LOINC terms in order to help categorize terms across LOINC Classes. For example, the LOINC Part LP29709-2 Cardiology is linked to LOINC terms that represent cardiology concepts across many different LOINC Classes, including chemistry, EKG, echo, documents, radiology, and survey. These category type links provide a way to gather clinically-related concepts beyond the relationships available in the Multiaxial hierarchy.

LoincPartLink.csv exceeds the row capacity of Excel and LibreOffice. Please be aware of this fact when using this file.

Please see the extended documentation, Release Notes, and Readme contained in this artifact for detailed reference information about this powerful resource and the ideas noted for future work. We welcome user feedback on these ideas, especially about linkages to external coding systems, the addition of category links to enable the use of LOINC Parts for organizing terms across Classes, and the format/size of the LoincPartLink.csv.

LOINC/IEEE Medical Device Code Mapping File

We have made significant changes to the contents and structure of this file since the last release and therefore it has been incremented to Version 3.0.

The file structure has been updated to match the HL7 FHIR ConceptMap model and the file now has the same content that is available via the LOINC FHIR terminology server. Specifically, the IEEE_DESCRIPTION, IEEE_DIM, AND IEEE_UOM_UCUM columns have been removed and an EQUIVALENCE column has been added. The IEEE description, dimensionality, and units of measure are maintained by and can be obtained from the IEEE 11073(TM) 10101 family of Standards for Health informatics - Point-of-care medical device communication.

Your feedback is needed for promoting these artifacts!

LOINC Change Snapshot File

The purpose of the LOINC Change Snapshot File is to provide a structured record of the key changes to LOINC content that occurred in this release. In this second Alpha release, we continue to only include LOINC Terms and Parts that have had a change in their Status since the last release (new LOINC terms are not included because they did not exist and therefore did not have a Status in the last release). There are separate .csv files for changes to LOINC terms and LOINC Parts.

Design notes and request for comment

In these files, we purposefully used the Property field to carry the identification of the attribute of the LOINC Term or Part that changed. This use of Property is the same meaning as in our FHIR CodeSystem representation, and not that of Property in the LOINC Fully Specified Name.

Within our internal LOINC management system, we are now tracking "change reasons" at the more detailed field level as described above. Therefore, we are able to report these field-level changes in separate rows of the Change Snapshot file rather than, or in addition to, the CHANGE_REASON_PUBLIC field in the LOINC table.

We would like user feedback on,

  • whether this file is useful in its current state,
  • whether we should make any changes either in terms of structure, the fields or attributes whose changes should be included in the file, or
  • if new .csv files should be added to reflect key changes in other artifacts, such as the LOINC PanelsAndForms or Answer Files.

LOINC Consumer Name File

We have continued to refine our new Consumer Names, which are available for all Laboratory LOINC terms and a subset of Clinical LOINC terms. The ConsumerName is created algorithmically, based on manually crafted labels (names) for each Part. These names do not represent each of the defining Parts of a given term, are not unique, and do not include an indicator that a term is deprecated.

We welcome your feedback about these names and expect to make iterative refinements to the approach over time.

The LOINC Consumer Names are intended for downstream display only and are not intended to be used at any point in the clinical workflow, nor for the purpose of mapping local terms to LOINC.

LOINC Group File

We are still looking for feedback about whether LOINC Groups are useful in their current state or whether there are changes, either in terms of content or structure, that would improve their usability. If you are using LOINC Groups, please drop us a note to tell us so that we can decide whether we should continue maintaining, publishing, and enhancing them.

LOINC Multiaxial Hierarchy File

In this release of the Multiaxial Hierarchy we continued to enhance the clinical LOINC hierarchy by adding more clinical Component Parts to the Component hierarchy. This change results in the LOINC terms using these Components being in a specific node in the hierarchy rather than in the ClinicalNotYetCategorized node. Two areas that we targeted for this release were vital signs and body measurements.

We continue to seek user feedback about our changes to the hierarchy, and especially about the approach to including the Class in the construction of the hierarchy nodes.

Notice of changes to the public LOINC data files in this release


We have implemented the following change to the LOINC Table (all formats):

Field Name: DisplayName
Formal Definition: This field contains a name that is more "clinician-friendly" compared to the current LOINC Short Name, Long Common Name, and Fully Specified Name. It is created algorithmically from the manually crafted display text for each Part and is generally more concise than the Long Common Name.
Action: ADD

As noted above, we have promoted Display Names to production status and included them in the LOINC table starting with this release.

LOINC Linguistic Variant File

We have implemented the following change to the LOINC Linguistic Variant File:

Formal Definition: Third major axis-timing of the measurement (e.g., point in time vs 24 hours)
Action: RENAME

This field name was updated to TIME_ASPCT (removing the "E") to align with the naming of this column in the main LOINC table.

Notice of changes to the public LOINC data files for the December 2020 Release


Notice of upcoming changes to this artifact in the December 2020 release:

Field Name: SPECIES
Formal Definition: Codes detailing which non-human species the term applies to. If blank, "human" is assumed.
Action: DELETE

This field has not been updated in many years. The values stored in the field are non-standard codes that are inconsistent in meaning and format. We decided that it would be better to eliminate the field rather than provide incomplete or confusing information. For this release we have emptied the field in preparation for deleting it from the database in the December 2020 release.

Thanks for reading, and happy holidays!