LOINC Hierarchy

This tool showcases the LOINC hierarchy that systematically categorize laboratory observations in healthcare systems for effective communication in EHR.

1. LOINC Code

LOINC (Logical Observation Identifiers Names and Codes) is a standardized coding system used globally to report laboratory and other clinical observations. The LOINC database contains over 71,000 terms, each described by a six-part structure that includes component, property, time aspect, system, scale, and method.

2. LOINC Part Code:

The six parts categorized in LOINC system are detailed below:

• Component indicates what is measured, evaluated, or observed.
• Property indicates characteristics of what is measured.
• Time aspect indicates interval of time over which the observation or measurement was made.
• System indicates context or specimen type within which the observation was made, e.g. blood or urine.
• Scale indicates the scale of measure.
• Method indicates the procedure used to make the measurement or observation.

Related: Major Parts of a LOINC term

The LOINC parts have codes beginning with LP. For example, LP14559-6 stands for Bacteria.

3. LOINC component

As discussed before, the LOINC component indicates the biological or clinical entities that are measured, evaluated or observed.

Quick Start Guide

1. Select an LOINC term from the data table. Alternatively, type keywords in a search box on the top right corner of the table to apply filtering conditions, and then select a LOINC
   • On the top left corner you can adjust number of entries shown in the table
2. Look for TreeList and TreeView (visualization version of TreeList) below that display the hierarchical structure where the given LOINC term fall in
3. You can click on the LOINC term or LOINC part of interest in TreeList and see the corresponding change hierarchical tree displayed in TreeView on the right.

Table

LOINC Info (top)

• LOINC: code of the LOINC term
• LOINC Description: the term’s official description in LOINC system (usually a combination of abbreviated medical terminologies)
• Component, Property, Time, System, Scale, Method: the six parts that are involved in the LOINC term (see detailed explanation of each part above)
• Long common name: detailed description of the LOINC term in full terminologies

Visualizations

TreeList

• The root of the tree shows the main component and its corresponding LOINC part codes. The child branches show LOINC parts with code and description that fall under the component. The end nodes show LOINC code with their description.
• The selected LOINC term from the top table would be highlighted in blue

TreeView

• TreeView directly visualize the TreeList structure displayed on the left
• The selected LOINC term from the top table or TreeList would be highlighted in red.

Use Cases

Laboratory tests can be reported via a range of coding systems, such as local codes and standardized LOINC codes, to represent distinct tests and methodologies. This adds a lot of complexity when leveraging electronic health records (EHRs) in clinical research. The LOINC Hierarchy tool mitigates this complexity by structuring LOINC codes within a hierarchical framework, which simplifies the process of identifying and comparing tests and facilitates the harmonization of data across different healthcare institutions.