What is LOINC, and how does it work?

LOINC—Logical Observation Identifiers, Names, and Codes—is a universal code system for identifying clinical information in electronic records. Although the Regenstrief Institute holds the copyright to LOINC, this versatile system is available for free at www.loinc.org.

The LOINC vocabulary standard identifies lab assays, clinical observations, and survey assessments by combining up to six attributes: component, property, timing, system, scale, and method. The User’s Guide documentation of Regenstrief’s open-source tool, RELMA, provides in-depth attribute descriptions. A LOINC term is numeric in nature with a check digit, to assure correct transcription. Changing even one of the six attributes points to a different term:

• Urine glucose on a chemistry analyzer in mg/dL = 2350-7

• Urine glucose from a dipstick = 5792-7

Every result field has both order-level LOINC terms and result-level LOINC terms. For example, a urinalysis panel will have a result term for appearance, pH, specific gravity, etc.

In general, think of the LOINC term as an international stock-keeping unit, or SKU, that accompanies the lab value to any clinician or repository. It does not replace the local code or name from the performing lab, but all computers loaded with the LOINC database can identify the assay. Algorithms or computations can also be applied to collate lab tests or observations with the same LOINC term.

What are best practices for implementing LOINC?

First, set priorities and goals by identifying the use case. Hospitals, public health organizations, research labs, data mining programs, in vitro diagnostic manufacturers, and governments might all approach LOINC implementation differently.

Using LOINC starts with training staff, implementing and evaluating local processes, monitoring local databases for ongoing changes to the test catalog, incorporating new LOINC releases twice each year, and mapping of your institution’s terms with LOINC terms—also known as cross-walking. I recommend using your test utilization report to start with top-volume assays. It also helps to reach out to national reference labs and instrumentation vendors to see if they can provide the LOINC terms for their assays.

Plan ahead to have the output formatted correctly for your information technology (IT) department. Additionally, identify all parties who have security access to edit the laboratory test database, and develop a reporting process that funnels all database changes to the designated LOINC mapper.

It is also imperative to involve medically trained personnel in the cross-walk development. The IT staff cannot do this alone.

The LOINC website contains a documentation section that is very helpful for implementing the system. In addition, the site has a planning task and activity duration schedule that project managers will find helpful, as well as an article from the Indiana Health Information Exchange summarizing 13 months of work encoding millions of terms across their hospitals and clinics. They demonstrated that just over 500 mappings covered all results for more than 99% of the values.

Is this a one-and-done project, or does it require ongoing updating?

No. Laboratory information systems are dynamic, and you must continually incorporate changes in instrumentation or kit reagents, as well as changes in referral lab contracts and options. As laboratory technology advances, so does LOINC.

Each LOINC terminology release also comes with a large amount of flux. Users risk a miscommunication in information exchange if the computer doesn’t recognize the LOINC term. In such a case the lab result message could go to an error log and not be transmitted correctly. This missing data affects patient safety.

The good news is that the maintenance phase of LOINC does not take up the same amount of time that the implementation phase takes. This ongoing task can reduce to a few hours a month, with one or two annual audits.

Pam Banning, MLS(ASCP)CM, PMP, is a healthcare data analyst in the Informatics Department at 3M Health Information Systems. She has also served on the Lab LOINC Committee for nearly 20 years. +Email: pdbanning@mmm.com