What is LOINC?

Standards enable interoperability

Health data needs to be portable. It needs to be structured so it can be exchanged between systems and used effectively. This concept is called interoperability. Standards allow for health data to be identified and exchanged through common means.

LOINC is an internationally recognized standard, one of several systems used to identify health data. LOINC is a database of identifiers for lab tests, vital signs, clinical documents, and other health information. Once data is identified with unique LOINC codes it can be exchanged with full understanding between disparate computer networks.

LOINC's important role

LOINC codes can be thought of as the "question" for a test or measurement. Using this analogy, the question could be "What is the patient's cholesterol level?" or "Does the patient smoke?" Each LOINC term carries enough detail to be meaningful and distinguish it from others. LOINC codes are used in conjunction with other data standards (such as SNOMED CT® for non-quantitative "answers") and then transferred between systems using messaging and resource standards like HL7® FHIR® and HL7® Version 2.

LOINC is a free and open standard

There is no cost to use LOINC. Anyone with a free LOINC user account may download the files or access the available tools.

Regenstrief Institute, the non-profit organization that created the standard in the mid-1990s and constantly develops LOINC, always welcomes requests for new terms to be vetted and added. There is no cost to submit a proposal. In fact, LOINC relies on submissions from the user community in order to grow and adapt the ever-expanding database of codes.

LOINC has served a crucial role in the COVID-19 pandemic

Coronavirus image by U.S. CDC
Coronavirus image by U.S. CDC
Coronavirus image by U.S. CDC
Coronavirus image by U.S. CDC
Coronavirus image by U.S. CDC
Coronavirus image by U.S. CDC
Mask up!
Requests from the community drive most new LOINC content, but LOINC is always poised to respond to new situations. The emergence of the virus strain now known as SARS-CoV-2 created an urgent need for rapid development and release of new LOINC codes.

LOINC’s team of clinical terminology developers reached out to the U.S. Centers for Disease Control and Prevention (CDC) in January 2020 to offer assistance to create new codes. The team worked in conjunction with the CDC on identifying the necessary parameters. Following a rapid but thoughtful terminology development and quality assurance process, the new SARS-CoV-2 codes were published on the LOINC web page as pre-release terms on Jan. 31 with a Special Use status. These initial terms were included with the June 2020 release of LOINC 2.68.

Response to COVID-19 needs continued throughout 2020. The LOINC team worked closely with Association of Public Health Laboratories (APHL), CDC, U.S. Food and Drug Administration (FDA), labs, in vitro diagnostic (IVD) manufacturers, and other stakeholders on the codes specifically related to SARS-CoV-2/COVID-19. In addition to more than 100 different terms for SARS-CoV-2 lab tests and panels, new LOINC codes were created for Ask on Order Entry (AOE) questions, convalescent plasma as well as public health case reporting for both the CDC and the World Health Organization (WHO), and COVID and telehealth-related documents. These terms are available on the LOINC website.

Responding to global needs at a critical time

Google is where much of the world goes for information. LOINC's rise in Google search results during 2020 highlights the influence of LOINC's response to the pandemic and provision of answers to emerging needs for information. The following graph shows the total number of times LOINC appeared in users' Google search results by week. Increased searches related to LOINC corresponded to significant events in the year.

Total Google Search
Impressions for LOINC in 2020

LOINC's Google search impressions for 2020

Google search impressions for LOINC in 2020 by week
Week in 2020

Term requests drive how LOINC grows and evolves

Requests from the community are the lifeblood of LOINC. Submissions are always welcome and can be made a number of ways including from the LOINC website.

New terms created in response to COVID-19 were only a fraction of the LOINC clinical terminology developers' work in 2020. The team gave top priority to requests related to SARS-CoV-2, often creating new terms in a matter of a few days, while at the same time processing a large volume of requests for new LOINC codes unrelated to the pandemic.

LOINC received a record number of term requests in 2020. A total of 514 requests representing 5,568 potential LOINC terms were received, an increase of 40% over 2019 and nearly double the 2018 total. Following a principle of transparency, all codes in development are detailed on the website. LOINC publishes detailed statistics about submissions including median turnaround time.

Each request—including those given high priority—goes through rigorous quality assurance review. Some requests require review by the LOINC Committee and/or subject domain experts. This thorough development ensures a high level of quality.

Total term requests received by year, 2013-2020
Demand for new LOINC terms has grown dramatically in the past several years. Regenstrief Institute has added new terminology developers to address the need.

The LOINC database contained 94,895 terms at the end of 2020

LOINC's work related to SARS-CoV-2/COVID-19 was only a portion of 2020's output. Between the two releases in June and December, a total of 2,526 new terms were added. Terms within the laboratory domain were 58% of these additions while 24% of terms were classed as clinical and 18% were for survey instruments.

LOINC's clinical terminology developers also made adjustments to existing terms. Some of these changes involve the Component or another of the six primary LOINC Parts. Most changes involve updates to secondary fields, such as the Long and Short names and term descriptions. LOINC's overarching policy allows a term to be modified as long as it does not change the meaning of the concept. No terms are ever deleted from the LOINC table. A total of 440 status changes and 10,626 term edits were made in 2020.

New LOINC terms added in 2020
v2.68 v2.69 Totals
Laboratory 709 747 1456 57.6%
Clinical 368 244 612 24.2%
Survey 218 240 458 18.1%
1295 1231 2526
Details on additions and changes within Version 2.68 and Version 2.69 are available with the release announcement for each. The Change Snapshot file has a structured record of key changes for a given release.

Total terms in LOINC database

LOINC content by type (2020)

Ancillary content

In addition to LOINC terms, Regenstrief Institute publishes other content related to the primary database. Ancillary content serves numerous purposes including aiding the adoption of LOINC and supporting research. These accessory files can be downloaded à la carte from the LOINC website or as part of the complete LOINC package.

Changes to accessory files

The LOINC Part File had its LoincPartLink.csv file split into primary and supplementary files. Detailed information regarding these files is available as a LOINC Knowledge Base article.

LOINC continues to evolve other release artifacts. Feedback is requested promote production maturity. The Change Snapshot file, Consumer Name file, Group file, and Multiaxial Hierarchy file are in need of user input.

Removed from the release

Content within LOINC's Top 2000+ file has been frozen for three years. While the file is still available for download, it has been removed from the full LOINC package while new ways are explored to present a common subset of LOINC terms based on more recent lab test frequency data.

LOINC previously published a set of common Unified Code for Units of Measure (UCUM) files. Since these are not specific to LOINC, they have been moved to the UCUM website.

As of the December 2020 release, the SPECIES field has been removed from the LOINC table. This column detailed the non-human species to which the terms applied. As the field had not been updated in several years, it was best to remove it entirely to avoid confusion and incomplete information. A notice regarding the pending deletion was given in the two prior releases.

Tools to support LOINC adoption

LOINC is not simply a database of clinical terminology. Several helpful tools have been produced to assist users in locating terms and mapping to local codes.

SearchLOINC and RELMA®

The inherent granularity of LOINC can make finding an appropriate term challenging. The web-based SearchLOINC application addresses this through a robust search syntax.

In December 2020, LOINC released a public Beta of its next-generation SearchLOINC application. This redesigned tool, available in tandem with the existing version, provides a more user-friendly interface for LOINC users while also allowing discovery of LOINC Parts, Groups, and Answer Lists.

RELMA is a free Windows application also allowing sophisticated searching and aiding users in mapping local terms to LOINC codes.

FHIR Terminology Service

The HL7® FHIR® standard provides a common API for sharing resources. LOINC leverages this platform to make available its terminology via programmatic means.

In 2020, LOINC created several Groups and value sets of terms for not only detection of SARS-CoV-2 but also for public health case reporting.

HL7 FHIR® logo
HL7, FHIR and the [FLAME] mark are the registered trademarks of Health Level Seven International. Use of these trademarks do not constitute an endorsement from HL7.

LOINC website

LOINC.org is the hub for everything regarding the standard. It's where newcomers can create a free LOINC username and password to access the various tools and services. The website is where users can download the LOINC table of codes along with numerous ancillary files.

LOINC's website is also the source of documentation and educational resources. In June 2020, LOINC established a new Knowledge Base locating the LOINC Users' Guide, RELMA User Manual, FAQs, and other information at a single searchable destination.

2020 Budget

Pie chart detailing LOINC revenue sources in 2020
Pie chart detailing LOINC expenses in 2020

2020 Funding Support

Over the years, LOINC has been supported financially by the Regenstrief Institute and many organizations and individuals. The LOINC team is thankful for the generous support in 2020 from:

LOINC thanks its 2020 donors for their support

A small team accomplishing a great deal

At the beginning of 2020, nearly half of the LOINC team already worked remotely and not in Regenstrief Institute's Indianapolis headquarters. This prior telework experience helped make for a smooth transition to entirely virtual collaboration beginning in mid-March of 2020. Thanks to numerous web-based meeting and project management tools, the LOINC team excelled in this environment. Still a relatively small group of professionals, the LOINC team rose to the challenges of 2020 despite its size and the unique situation caused by the pandemic.

The LOINC team is a finely-tuned collection of clinical terminology developers, software and systems engineers, and project management staff. Each member brings unique talents and skills to a unified mission.

LOINC Team photo courtesy of Zoom
The LOINC Team is well accustomed to working together in virtual environments—a tremendous asset for the Year 2020.

The principles behind LOINC's purpose


We imagine a world where people experience optimal health catalyzed by a seamless network of health information systems.


Our mission is to develop and advance the adoption of open data standards that enable efficient transmission, understanding, and use of health data by promoting open terminology standards integrated into every clinical information system that shares or aggregates data. Yes, it sounds audacious, but standards demonstrate the benefit of a network effect and become more valuable as more people and systems use them. We are committed to a health ecosystem where data is available with open, consistently vetted standards that unlock the potential for information systems and applications to improve health decision-making and care.

Our approach

How do we approach this fundamental challenge? We learn. As individuals and as a collective community, we apply a learning mindset to every aspect of our work.

What do we learn? We learn to create, curate, and deliver data standards that make health data more portable and understandable to various computer systems. We learn to cultivate a vibrant community of practice that embodies our guiding principles and advances towards our vision.

How does this actually play out in our work? Learning is the standard we expect of ourselves. We learn to be better each day. We look at each requested term, proposed edit, project, code routine, and task as an opportunity to learn more. By doing so, we grow as individuals and as a community. And we move closer to our goal.

Photo by Kelly Sikkema on Unsplash

Guiding principles for open terminology development

The following principles are the shared beliefs that guide our behavior as we develop and advance open data standards. The principles support cohesion of our communities cohesion and provide a framework for our collective progress. They serve as a beacon for others who share these ideals. We remain committed to continual improvement based upon the following principles.


We encourage others developing standard health terminologies to adopt these guiding principles for their projects and initiatives.

A truly international standard

LOINC is in nearly every country around the world and has been adopted as a national standard in more than a dozen countries.

LOINC surpassed 100,000 registered users in 2020. The countries highlighted in blue on the map indicate those with at least one LOINC registered user.

World atlas showing LOINC user representation by country

Translations enable adoption of LOINC

LOINC views the translation of terms into multiple language as the key to international adoption. LOINC takes a novel approach to this monumental feat. Rather than translating each term in its entirety, volunteers translate the unique pieces ("Parts") that make up LOINC terms. These atomic pieces are then compiled to create a full LOINC name for each term.

LOINC is indebted to its global network of volunteer translators. The standard has been translated from the original English into 15 linguistic variants. Additional translations are always welcomed.

zh-CNChinese (China)
nl-NLDutch (Netherlands)
de-ATGerman (Austria)
de-DEGerman (Germany)
et-EEEstonian (Estonia)
fr-BEFrench (Belgium)
fr-CAFrench (Canada)
fr-FRFrench (France)
it-ITItalian (Italy)
ko-KRKorean (Korea, Republic of)
pt-BRPortuguese (Brazil)
ru-RURussian (Russian Federation)
es-ARSpanish (Argentina)
es-ESSpanish (Spain)
tr-TRTurkish (Turkey)

Robust community outreach and collaboration

LOINC recognizes the important roles of its users and of the larger health standards community.

LOINC participates in several collectives of organizations with a common goal of data interoperability. In 2020, LOINC was invited to join the Joint Initiative Council (JIC). This group of nine standards development organizations (SDOs) transcend national boundaries to work collaboratively to provide global, coordinated—not competitive—standards that address real-world healthcare issues. JIC published a white paper explaining how the nine SDOs work together to transform the global healthcare system.

LOINC users form a vibrant community with a wealth of diverse expertise, resources, and knowledge. Regenstrief Institute has developed several means of fostering community participation and interaction. The LOINC team is responsive to user questions and comments. It handled 2,871 support tickets in 2020, a 48% increase over the previous year. LOINC's Clinical Terminology Developers continue to give high priority to questions concerning SARS-CoV-2/COVID-19.

Other ways to interact and receive information include the LOINC mailing list, Twitter, LinkedIn, and User Forum.

HL7 International
Joint Initiative Council (JIC)
Health Standards Collaborative (HSC)
LOINC Committee structure

LOINC Committee

To help guide LOINC development, Regenstrief Institute organized the LOINC Committee. With volunteers from academia, industry, and government, the LOINC Committee serves as the main advisory body for LOINC.

The LOINC Committee is comprised of the members of its composite committees. The committee's organizational structure is shown in the adjacent diagram. Members of the LOINC community interested in joining a committee can visit the LOINC website for details and to apply.

Current committee rosters are also available on the site.

Very successful virtual events underscore LOINC's importance

To put it mildly, 2020 was a challenge.

The LOINC Team had been accustomed to holding in-person conferences twice annually. Restrictions on travel and in-person events drastically altered this course. The LOINC Conference scheduled for March in Indianapolis had to be scrapped. In its place a special virtual meeting was held on March 26 to distribute information and answer questions regarding the use of LOINC in SARS-CoV-2/COVID-19 lab tests. This three-hour webinar included guests from the Association of Public Health Laboratories (APHL), The Office of the National Coordinator for Health Information Technology (ONC), SNOMED International, and Intermountain Healthcare.

In lieu of a typical LOINC Conference held outside the U.S., the team put together its first virtual LOINC Conference. The result was beyond expectations. Participants from 40 countries joined, dwarfing the draw of previous conferences. The four-day schedule preserved many hallmarks of LOINC's in-person conferences including the keynote address known as the Clem McDonald Lecture, educational workshops, presentations from LOINC community members, and the Laboratory and Clinical LOINC Committee meetings.

LOINC Webinar for SARS-CoV-2/COVID-19

This three-hour webinar was held on March 26, 2020. Nearly 700 individuals signed up to attend the event.

Watch Recording

October 2020 LOINC Conference

The first-of-its-kind virtual LOINC Conference was held on Oct. 13-16, 2020. It featured more than 300 participants representing 40 countries.

View Schedule and Resources

LOINC Award for Distinguished Achievements

Lin Zhang aka Forest
Lin "Forest" Zhang, 2020 recipient
Lin Zhang, a LOINC volunteer from China, was named the 2020 recipient of the LOINC Award for Distinguished Contributions. Also known as Forest, Lin has been a passionate supporter of LOINC for much of its existence and has served as a prodigious translator of the LOINC terminology and documentation into Simplified Chinese—key to its adoption in the country. His work, to date, spans 32 LOINC release cycles and includes the LOINC Users' Guide, the RELMA Manual, and the UCUM standard.

LOINC creator Clem McDonald, MD, presented the award virtually to Lin at the Oct. 2020 LOINC Conference. In presenting the award, Dr. McDonald said of Lin, "You have had a deep, important, and expansive influence on LOINC, its evolution, and its international success. You are richly deserving of this award and we all love you."

Established in 2016, the LOINC Award for Distinguished Contributions honors an individual who has made sustained and enduring contributions that advance health data interoperability with LOINC. The award is typically given each spring at the LOINC Conference event in the U.S.

Stanley M. Huff Education Award

Stanley M. Huff
Stanley M. Huff, MD
To honor one of LOINC's most loyal and impactful supporters, the Stanley M. Huff Education Award was established in 2020. Full-time students are encouraged to apply for this award which provides free access to a semiannual LOINC Conference.

Former LOINC Director Daniel Vreeman, DPT, presented the award virtually to Dr. Huff at the October 2020 LOINC Conference. Dr. Vreeman said, "This new award not only recognizes its recipient's longstanding leadership, his contribution, his commitment to life-long learning, and passion for mentoring, it also sets up opportunities for selected students to be able to attend LOINC Conferences with no registration fees. So it pays it forward, just like the awardee."

The first recipient of the Stanley M. Huff Education Award will be named at the March 2021 LOINC Conference.

Regenstrief Institute
Regenstrief Institute

Regenstrief Institute is home to LOINC

Regenstrief Institute, Inc. is a non-profit 501(c)3 research organization driven by a mission to connect and innovate for better health. Regenstrief Institute serves as the overall steward and standards development organization (SDO) for LOINC.

The LOINC team within Regenstrief maintains the LOINC database and supporting documentation, processes submissions and edits to the content, develops and curates accessory content (descriptions, hierarchies, other attributes, etc.), develops the RELMA mapping program, and coordinates LOINC releases. The team provides guidance to the LOINC community with understanding and implementing LOINC and promotes the adoption of LOINC as a data standard worldwide.

What's with the pig? Simply put, LOINC rhymes with “oink” so we’ve adopted a pig as our official mascot.
LOINC Pig Mascot

Select biomedical articles published in 2020 referencing LOINC

Visit the U.S. Library of Medicine's PubMed tool for the full list of historical articles pertaining to LOINC.