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LOINC® (Logical Observation Identifiers, Names and Codes) is a public use set of codes and names for electronic reporting of clinical laboratory test results in particular

developed by keywords
The Regenstrief Institute, Indianapolis and the LOINC committee (initiated in 1994). Clinical vocabulary, nomenclature, laboratory test orders, clinical laboratory result, standards
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Available for download and free use.  bullet  LOINC database (in MS Access™, PDF and tab-delimited formats), RELMA®, associated documentation  in Chinese  LOINC download in simplified Chinese
LOINC® - Logical Observation Identifiers, Names and Codes.

LOINC codes are universal identifiers for laboratory test results and other clinical observations.

LOINC has been developed to facilitate particularly the transmission and storing of clinical laboratory results (blood haemoglobin or serum potassium etc.) to support clinical care, outcomes management, and clinical research. Nearly 20,000 of around 32,000 observation terms contained within LOINC relate to laboratory testing. LOINC is designed to be compatible with HL7 messages.

" LOINC has been endorsed by the American Clinical Laboratory Association and the College of American Pathologists. It has been adopted as an alternate test reporting code by large commercial laboratories including Quest, LabCorp, Mayo Medical Laboratories, and MDS Labs; large HMOs including Kaiser Permanente and Aetna; governmental organizations including the CDC, DOD, VA, and NLM; and has also been adopted by Germany, Switzerland and two Canadian provinces. "

LOINC is available in (simplified) Chinese and is being translated into Spanish and German.

The LOINC database can be downloaded for free use (users cannot modify official codes but can extend them locally). See the abstracts below for further information on LOINC.

Associated software

RELMA® (the Regenstrief LOINC Mapping Assistant): a Windows-based program designed to support browsing and search of the LOINC database and mapping local test codes to LOINC codes.

RELMA® can be downloaded for free use from the Regenstrief Institute website for installation on a computer (runs in Windows 95, 98, NT, 2000 and XP), or can be run over the internet using a web browser (requires Citrix© client software).


LOINC and standardisation

On March 21 2003, the Departments of Health and Human Services, Defense, and Veterans Affairs announced the first set of five uniform standards for the electronic exchange of clinical health information to be adopted across all US federal agencies. LOINC® was adopted "to standardize the electronic exchange of clinical laboratory results".

The US government's Consolidated Health Informatics Programme (the healthcare component of President Bush's eGov Initiatives) published a Standards Adoption Report that included the following summary and comment on LOINC:

"LOINC is the most complete, flexible and available terminology of laboratory test result names. CHI notes the wide acceptance of Laboratory LOINC in both the public and private sector. The recommendation is accompanied by the need to make improvements in structure of Laboratory LOINC to make it more useful, less ambiguous and more robust. CHI recommends continued federal funding to support this goal. The developers of Laboratory LOINC are already working to meet this requirement. CHI also notes that the recommendation of Laboratory LOINC is specific for that section of the LOINC code set."

Huff SM, Rocha RA, McDonald CJ, et al. Development of the Logical Observation Identifier Names and Codes (LOINC) Vocabulary. J Am Med Inform Assoc. 1998 May-Jun;5(3):276-92.

[PubMed Central]

" The LOINC (Logical Observation Identifier Names and Codes) vocabulary is a set of more than 10,000 names and codes developed for use as observation identifiers in standardized messages exchanged between clinical computer systems. The goal of the study was to create universal names and codes for clinical observations that could be used by all clinical information systems. The LOINC names are structured to facilitate rapid matching, either automated or manual, between local vocabularies and the universal LOINC codes. If LOINC codes are used in clinical messages, each system participating in data exchange needs to match its local vocabulary to the standard vocabulary only once. This will reduce both the time and cost of implementing standardized interfaces. The history of the development of the LOINC vocabulary and the methodology used in its creation are described. "

McDonald CJ, Huff SM, Suico JG et al. LOINC, a universal standard for identifying laboratory observations: a 5-year update. Clin Chem. 2003 Apr;49(4):624-33.

[PubMed]   []

" The Logical Observation Identifier Names and Codes (LOINC) database provides a universal code system for reporting laboratory and other clinical observations. Its purpose is to identify observations in electronic messages such as Health Level Seven (HL7) observation messages, so that when hospitals, health maintenance organizations, pharmaceutical manufacturers, researchers, and public health departments receive such messages from multiple sources, they can automatically file the results in the right slots of their medical records, research, and/or public health systems. For each observation, the database includes a code (of which 25 000 are laboratory test observations), a long formal name, a "short" 30-character name, and synonyms. The database comes with a mapping program called Regenstrief LOINC Mapping Assistant (RELMA™) to assist the mapping of local test codes to LOINC codes and to facilitate browsing of the LOINC results. Both LOINC and RELMA are available at no cost from The LOINC medical database carries records for>30 000 different observations. LOINC codes are being used by large reference laboratories and federal agencies, e.g., the CDC and the Department of Veterans Affairs, and are part of the Health Insurance Portability and Accountability Act (HIPAA) attachment proposal. Internationally, they have been adopted in Switzerland, Hong Kong, Australia, and Canada, and by the German national standards organization, the Deutsches Instituts fur Normung. Laboratories should include LOINC codes in their outbound HL7 messages so that clinical and research clients can easily integrate these results into their clinical and research repositories. Laboratories should also encourage instrument vendors to deliver LOINC codes in their instrument outputs and demand LOINC codes in HL7 messages they get from reference laboratories to avoid the need to lump so many referral tests under the "send out lab" code. "

Bakken S, Cimino JJ, Haskell R, Kukafka R, Matsumoto C, Chan GK, et al. Evaluation of the clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures. J Am Med Inform Assoc 2000;7:529-538

[PubMed]   [PubMed Central]

" OBJECTIVE: The purpose of this study was to test the adequacy of the Clinical LOINC (Logical Observation Identifiers, Names, and Codes) semantic structure as a terminology model for standardized assessment measures. METHODS: After extension of the definitions, 1, 096 items from 35 standardized assessment instruments were dissected into the elements of the Clinical LOINC semantic structure. An additional coder dissected at least one randomly selected item from each instrument. When multiple scale types occurred in a single instrument, a second coder dissected one randomly selected item representative of each scale type. RESULTS: The results support the adequacy of the Clinical LOINC semantic structure as a terminology model for standardized assessments. Using the revised definitions, the coders were able to dissect into the elements of Clinical LOINC all the standardized assessment items in the sample instruments. Percentage agreement for each element was as follows: component, 100 percent; property, 87.8 percent; timing, 82.9 percent; system/sample, 100 percent; scale, 92.6 percent; and method, 97.6 percent. DISCUSSION: This evaluation was an initial step toward the representation of standardized assessment items in a manner that facilitates data sharing and re-use. Further clarification of the definitions, especially those related to time and property, is required to improve inter-rater reliability and to harmonize the representations with similar items already in LOINC. "

contact links

Kathy Mercer
Regenstrief Institute, Inc.
1050 Wishard Boulevard
Indianapolis, IN 46202, USA

Tel: (317) 630-7433


 bullet  LOINC  bullet  LOINC database [download]  bullet  LOINC download in simplified Chinese  bullet  RELMA®  bullet  Complete bibliography on LOINC  bullet  Regenstrief Institute  Auf Deutsch  LOINC in Germany (DIMDI)  bullet  LOINC as a standard [OC]
Entry on OpenClinical: 12 December 2004
Last main update: 12 December 2004
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