Nursing Terminology Update

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Logical Observation Identifiers Names & Codes (LOINC)

Submitted by Susan Matney

On December 18, 2002, the American Nurses Association (ANA) Committee for Nursing Practice Information Infrastructure recognized the Logical Observation Identifiers Names & Codes (LOINC) as the thirteenth terminology for use by nursing (Thede, 2003). This terminology was originally created to define universal names and codes for laboratory findings. In the past five years it has been expanded to include other clinical measurements including assessment items of relevance to nursing such as vital signs, obstetric measurements, clinical assessment scales, assessments from standardized nursing terminologies, and research instruments (Bakken et al., 2000; Huff et al., 1998).

The LOINC vocabulary is a publicly available, no cost database that provides a set of universal names and codes identifying laboratory and clinical test results which can be used in computer databases or transmitted in electronic messages (Forrey et al., 1996; Huff et al., 1998). Work on LOINC first began in 1994 by the National Library of Medicine and the Agency for Health Care Policy and Research at the Regenstrief Institute, a research foundation affiliated with the Indiana University School of medicine (Huff et al., 1998). The rationale for the development of LOINC was to create universal names and codes for measurements used in a laboratory setting. There were a growing number of laboratory systems using internally defined names and codes that were specific to the vendor or the specific institution. The goal of the LOINC committee was to create codes that could be universally used by all systems and could therefore easily participate in clinical data exchange. Another objective in the development of LOINC was to structure the names in a format that could facilitate rapid matching, either automated or manual, between local vocabularies and the universal LOINC codes. The different LOINC axes described below enable rapid matching.

LOINC formal names and codes are created for laboratory results and clinical variables with numeric, coded or narrative text results. The current version has over 20,000 lab codes and 10,000 clinical codes. The LOINC codes are not intended to transmit all possible information about an observation; they are only intended to identify the clinical observation. The LOINC names are used in resulting specific patient observations during patient care. Although LOINC does not contain the coded values for the names, there are suggested answer lists for each ordinal (e.g., 1+, 2+, 3+, 4+) and nominal code (e.g., clear, rhonchi, rales and wheezes for breath sounds)

LOINC Structure

The ANA recognized LOINC as a nomenclature. A nomenclature is a system of terms composed according to pre-established composition rules (de Keizer, 2000). Nomenclatures provide a common reference point so that data can be communicated between health care systems (Payne, 1999). LOINC semantic structure is modeled using the multi-axial representational approach. The multi-axial approach uses aggregate or pre-coordinated expressions. Each LOINC record corresponds to a single result. The LOINC axes include component, kind of property, time aspect, system, precision and type of method.

1. Component (analyte) - the substance or entity that is measured, evaluated or observed (e.g., systolic blood pressure, pain onset, and sodium).
2. Kind of Property - The characteristic or attribute of the analyte that is measured, evaluated, or observed (e.g., length, volume, time stamp, mass, ratio, number, temperature).
3. Time Aspect - The interval of time over which the observation or measurement was made (e.g., point in time, 24 hour).
4. System - The system (context) or specimen type within which the observation was made (e.g., urine, serum, fetus, patient, family).
5. The type of Scale – The scale of the measure (e.g. quantitative (a true measurement), ordinal (a ranked set of options), nominal (e.g., E. coli; Staphylococcus aureus), or narrative (e.g., dictation results from x-rays)).
6. Type of Method - The procedure used to make the measurement or observation. It is only used when it makes an important distinction in sensitivity or specificity. Method is the only axis that is optional.

The fully specified name for temperature taken rectally at a specific point in time looks like this:

8332-9 BODY TEMPERATURE:TEMP:PT:RECTUM:QN::

The LOINC database includes columns for each of the six parts (axes) of the name. In addition, it also contains short names, related words, synonyms, and comments for all observations. Related words ("synonyms") are included to facilitate searches for individual laboratory test and clinical observation results. The table also contains information about the amount, route, and timing of physiologic or pharmacologic challenges.

The LOINC database is presented as an electronic document grouped by "common sense" categories to make it easier to find general areas of interest. It is divided first into two main categories, “lab” and “clinical.” The laboratory portion is further divided into the usual categories of chemistry, hematology, serology, microbiology (which includes parasitology and virology), and toxicology; there are also categories for drugs and the cell counts. The clinical portion of the LOINC database contains classes that are pertinent for nursing such as body measurement, intake and output, neonatal Apgar measures, obstetrical studies and measures, respiratory measures & ventilator management, nursing survey instruments, vaccination records, vital signs and volume. The LOINC database also includes fully specified names for two other ANA recognized terminologies, the Omaha System and the Home Health Care Classification system (Martin & Scheet, 1992; Saba & Zuckerman, 1992).

LOINC Committee and Code submission

The Clinical LOINC Committee is responsible for the development and maintenance of the clinical LOINC codes. The Regenstrief Institute in Indianapolis, Indiana, maintains the LOINC database and supporting documentation. A formal submission process is outlined in the LOINC manual. After the submission is reviewed and approved by the LOINC committee, the term is assigned a code number in sequential order, which also is to say the code itself has no meaning (Cimino, 1997).

LOINC codes are never deleted. Duplicates that are identified are deprecated (inactivated), documented with change reason, dates, who did, and what is the suggested map to LOINC code.

Examples of Measurements used in Nursing currently in LOINC

Future of Nursing and LOINC

There is still a lot of LOINC content that needs to be created in order to have a comprehensive set of nursing measurements. Work currently in progress includes cardiovascular assessments, genitourinary assessment and air ambulance codes (Thompson, 2002). The open development process associated with the creation of the LOINC database supports the submission of codes from those with content expertise. A process is needed to enhance the rate at which nursing content is added to LOINC; therefore, a subcommittee of LOINC focused on nursing content is planned (Matney, 2003).

Conclusion

LOINC is the thirteenth ANA recognized language. The LOINC database and semantic multi-axial structure has been presented with examples of fully specified LOINC names. More codes specific to nursing are planned for future submission.

References

Bakken, S., Cimino, J. J., Haskell, R., Kukafka, R., Matsumoto, C., Chan, G. K., & Huff, S. M. (2000). Evaluation of the Clinical LOINC (Logical Observation Identifiers, Names, and Codes) Semantic Structure as a Terminology Model for Standardized Assessment Measures. JAMIA, 7(6), 529-538.

Cimino, J. J. (1997). Desiderata For Controlled Medical Vocabularies in the Twenty-First Century. Paper presented at the IMIA Working Group 6, Jacksonville, FL.

de Keizer, N. F., Abu-Hanna, A., Zwetslook-Schonk, J.H.M. (2000). Understanding Terminological Systems I: Terminology and Typology. Methods of Information in Medicine, 39, 16-21.

Forrey, A. W., McDonald, C. J., DeMoor, G., Huff, S. M., Leavelle, D., Leland, D., Fiers, T., Charles, L., Griffin, B., Stalling, F., Tullis, A., Hutchings, K., & Baenziger, J. (1996). Logical observation identifier names and codes (LOINC) database: a public use set of codes and names for electronic reporting of clinical laboratory test results. Clinical Chemistry, 42(1), 81-90.

Huff, S. M., Rocha, R. A., McDonald, C. J., De Moor, G. J. E., Fiers, T., Bidgood, W. D., Jr., Forrey, A. W., Francis, W. G., Tracy, W. R., Leavelle, D., Stalling, F., Griffin, B., Maloney, P., Leland, D., Charles, L., Hutchins, K., & Baeziger, J. (1998). Development of the LOINC (Logical Observation Identifier Names and Codes) Vocabulary. JAMIA, 5(3), 276-292.

Johnson, M., Maas, M., & Moorhead, S. (Eds.). (2000). Nursing Outcomes Classification (NOC) (2nd ed.). St. Louis: C.V. Mosby.

Martin, K. S., & Scheet, N. J. (1992). The Omaha System: Applications for community health nursing. Philadelphia: WB Saunders.

Matney, S., Bakken, S., Huff, S.M. (2003). Representing Nursing Assessments in Clinical Information Systems Using the Logical Observation Identifiers, Names, and Codes (LOINC) Database. Journal of Biomedical Informatics, In Press.

Payne, T. H., Sengupta, S., Sittig, D.F. (1999). Electronic Exchange of Patient Information: The Infrastructure for Electronic Health Records. In G. F. Murphy, Hanken, M.A., Water, K.A. (Ed.), Electronic Health Records: Changing the Vision (pp. 129-130). Philadelphia: WB Saunders.

Saba, V. K., & Zuckerman, A. E. (1992). A new home health classification method. Caring Magazine, 11(9), 27-34.

Thede, L. Q. (2003). Informatics and Nursing: Opportunities & Challenges (2nd ed. ed.). Philadelphia: Lippincott Williams & Wilkins Publishers.

Thompson, C. B., Schaffer, J. (2002). Minimum data set development: Air transport time-related terms. International Journal of Medical Informatics, 65(2), 121-133.
Author’s Bio

Susan Matney, M.S., R.N.

Ms. Matney received her master’s of science degree in nursing informatics from the University of Utah in 1997. Susan has been a nurse for over 20 years and has a background in nursing administration and labor and delivery. She currently works for Intermountain Health Care as the manager of the Health Data Dictionary (HDD) team. She is responsible for the coded terminology used by all the computerized patients records as well as the clinical data models used to store the data. Susan is a member of the American Medical Informatics Association, Utah Nursing Informatics Network and the American Nurses Association. She is certified in inpatient obstetrics.