The Role of LOINC

LOINC provides access to standardized, structured data and is fundamental to any informatics strategy.

Love it or hate it, LOINC (Logical Observation Identifiers Names and Codes) is here to stay. Claiming more than 42,000+ registered users in 171 countries, LOINC is currently the most accepted vocabulary to electronically report clinical laboratory test results in the world. In the U.S., the Office of the National Coordinator for Health Information Technology (ONC)1 has officially recognized LOINC as the federally required2 standard for identification of observations in laboratory tests in its updated December 2017 Interoperability Standards Advisory (ISA). The ISA is a coordinated catalog of standards and implementation specifications that are available for use by the health IT industry to meet interoperability needs.

Why is LOINC important?

It has long been recognized that access to standardized, structured data is fundamental to any future, grand healthcare informatics strategy. Large scale data analytics are key to reducing the cost of healthcare (now nearly 18% of the US’s GDP).3 We are already seeing the benefits of artificial intelligence and machine learning used in clinical data analytics in many areas of the healthcare ecosystem—from new discoveries through cohort analysis of non-obvious clusters of interrelated conditions, treatments and outcomes; to care path optimization by analyzing both clinical and financial data; to a bigger focus on early detection, prevention and personalized care through the analysis of genomic, socio-demographic and lifestyle data.

The clinical analytics space is already getting crowded with more than four hundred companies—from early startups to large, corporate entities (IBM Watson Analytics) vying for attention. None has any value unless you get access to large sets of both structured and unstructured medical and financial data, across group, state, national and even international data repositories. Aside from volume, these population data sets will need to use common clinical vocabularies. Currently, that means ICD-10 for diagnosis codes, CPT and ICD-10 for procedure codes, RxNorm codes for drugs, and LOINC (and later SNOMED-CT)4 for clinical laboratory orders and results.

The U.S. government is finally subscribing to a grand vision for Healthcare IT that calls for clear, unambiguous, interoperability standards. The 21st Century Cures Act was voted into law on December 14, 2016 and aims to facilitate data exchange, favoring exchange standards developed in the private sector. Some may say that adding a myriad of standards amounts to nothing more than government overreach. However, for the laboratory, mandating these new standards is also a major step towards guaranteeing true interoperability, substantially reducing instrument deployment cost and giving laboratory customers more flexibility in working with multiple vendors.

Heed the Warning

For IVD vendors and laboratories, the ONC’s Shared Nationwide Interoperability Roadmap is very clear in that it expects federal and state agencies to begin incorporating technical standards and certification requirements in grants and contracts that fund health IT adoption and Medicaid financing of IT systems. As it relates to LOINC, the FDA already added LOINC to its list of recognized standards in January of 2016.

The clinical laboratory is a treasure trove of multi-dimensional and time series patient data that is still very much underutilized—understandably, because it is currently impossible to compare large population results across multiple laboratories. This is where LOINC can play an important role. Unfortunately, to use LOINC, laboratories must still map their local codes to terms in the standard, a process that remains unnecessarily complex and error-prone as there is not always a one-to-one relationship between the tests that are run on laboratory instruments and existing LOINC codes. Erroneous mapping can also result in the reporting of incorrect patient test results with potentially detrimental consequences.

To address this, the IVD Industry Connectivity Consortium (IICC) presented a proposal for vendors to use when publishing LOINC for their IVD Tests at the November 8, 2016 Workshop on Promoting Semantic Interoperability of Laboratory Data at the National Institutes of Health (NIH) in Bethesda, MD. The workshop was organized by the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) to receive and discuss input from industry stakeholders regarding proposed approaches to promoting the semantic interoperability of laboratory data between in vitro diagnostic devices and database systems, including laboratory information systems (LISs) and electronic health records (EHRs).

The IICC approach, presented by Ed Heierman, should make it easier for laboratories to find the correct LOINC codes for the tests that they run on their instruments. The format is human readable, assuring that laboratory personnel select the appropriate LOINC codes for vendor IVD test results used by their laboratory. IVD software systems may also be able to automatically map the correct IVD vendor test result to a LOINC code.

The proposed LOINC Enhanced Vendor Test Format would contain extended data elements, including the manufacturer, the instrument model, an instrument universal identifier (UID), the vendor transmission code, vendor specimen description, vendor result description, the test name and optional data elements (e.g., a reference ID to the package insert, additional instructions or comments related to the test). The proposed data exchange format will use JSON (JavaScript Object Notation), a lightweight, global industry standard format with a simple syntax that is also human readable.

As of this writing, the proposed EVTF format had received positive feedback and will now be formalized in a specification. It is likely that IVD vendors will make their LOINC EVTFs available for download in a similar fashion to product inserts and material safety data sheet, but some of this remains to be determined.

For more information:


  1. The ONC (Office of the National Coordinator for Health Information Technology) is a staff division of the Office of the Secretary, within the U.S. Department of Health and Human Services.
  2. 2015 Edition Health Information Technology (Health IT) Certification Criteria, 2015 Edition Base Electronic Health Record (EHR) Definition, and ONC Health IT Certification Program Modifications
  3. 2016 National Health Expenditure Accounts (NHEA)
  4. SNOMED-CT is in feedback stage

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