A - LOINC Database Structure

This section last updated: 2024-02-29 (9 months ago)

LOINC Table Structure

LOINC_NUM

Type: Text
Width: 10

The unique LOINC Code is a string in the format of nnnnnnnn-n.

COMPONENT

Type: Text
Width: 255

First major axis-component or analyte

PROPERTY

Type: Text
Width: 255

Second major axis-property observed (e.g., mass vs. substance)

TIME_ASPCT

Type: Text
Width: 255

Third major axis-timing of the measurement (e.g., point in time vs 24 hours)

SYSTEM

Type: Text
Width: 255

Fourth major axis-type of specimen or system (e.g., serum vs urine)

SCALE_TYP

Type: Text
Width: 255

Fifth major axis-scale of measurement (e.g., qualitative vs. quantitative)

METHOD_TYP

Type: Text
Width: 255

Sixth major axis-method of measurement

CLASS

Type: Text
Width: 255

An arbitrary classification of the terms for grouping related observations together. The current classifications are listed in Appendix B. We present the database sorted by the class field within class type (see field 23). Users of the database should feel free to re-sort the database in any way they find useful, and/or to add their own classifying fields to the database.

The content of the laboratory test subclasses should be obvious from the subclass name.

VersionLastChanged

Type: Text
Width: 255

The LOINC version number in which the record has last changed. For records that have never been updated after their release, this field will contain the same value as the loinc.VersionFirstReleased field.

CHNG_TYPE

Type: Text
Width: 255

A coded field that indicates the last type of change applied to the record. This field should be used in conjunction with the VersionLastChanged field to determine what version the value in CHNG_TYPE field occurred in.

Change Type Codes

• DEL = The concept was deprecated
• ADD = The concept was added
• PANEL = addition or removal of child elements or change in the conditionality of child elements in the panel or in sub-panels contained by the panel
• NAM = The COMPONENT field of the concept was changed
• MAJ = The PROPERTY, TIME_ASPCT, SYSTEM, SCALE_TYPE, or METHOD_TYP field of the concept was changed
• MIN = Fields other that those specified for NAM or MAJ change types were updated. (Exceptions: RELATEDNAMES2, CONSUMER_NAME, VersionLastChanged, VersionFirstReleased, CHANGE_REASON_PUBLIC, and STATUS_TEXT)
• UND = The concept was moved from the DEPRECATED status to either ACTIVE, TRIAL, or DISCOURAGED

DefinitionDescription

Type: Memo
Width: N/A

Narrative text that describes the LOINC term taken as a whole (i.e., taking all of the parts of the term together) or relays information specific to the term, such as the context in which the term was requested or its clinical utility.

STATUS

Type: Text
Width: 255

ACTIVE = Concept is active. Use at will.

TRIAL = Concept is experimental in nature. Use with caution as the concept and associated attributes may change.

DISCOURAGED = Concept is not recommended for current use. New mappings to this concept are discouraged; although existing may mappings may continue to be valid in context. Wherever possible, the superseding concept is indicated in the MAP_TO field in the MAP_TO table (see below) and should be used instead.

DEPRECATED = Concept is deprecated. Concept should not be used, but it is retained in LOINC for historical purposes. Wherever possible, the superseding concept is indicated in the MAP_TO field (see below) and should be used both for new mappings and updating existing implementations.

CONSUMER_NAME

Type: Text
Width: 255

An experimental (beta) consumer friendly name for this item. The intent is to provide a test name that health care consumers will recognize.

CLASSTYPE

Type: Number
Width: N/A

1=Laboratory class; 2=Clinical class; 3=Claims attachments; 4=Surveys

FORMULA

Type: Memo
Width: N/A

Contains the formula in human readable form, for calculating the value of any measure that is based on an algebraic or other formula except those for which the component expresses the formula. So Sodium/creatinine does not need a formula, but Free T3 index does.

EXMPL_ANSWERS

Type: Memo
Width: N/A

For some tests and measurements, we have supplied examples of valid answers, such as “1:64”, “negative @ 1:16”, or “55”.

SURVEY_QUEST_TEXT

Type: Memo
Width: N/A

Verbatim question from the survey instrument

SURVEY_QUEST_SRC

Type: Text
Width: 50

Exact name of the survey instrument and the item/question number

UNITSREQUIRED

Type: Text
Width: 1

Y/N field that indicates that units are required when this LOINC is included as an OBX segment in a HIPAA attachment

RELATEDNAMES2

Type: Memo
Width: N/A

This field was introduced in version 2.05. It contains synonyms for each of the parts of the fully specified LOINC name (component, property, time, system, scale, method).

SHORTNAME

Type: Text
Width: 255

Introduced in version 2.07, this field contains the short form of the LOINC name and is created via a table-driven algorithmic process. The short name often includes abbreviations and acronyms.

ORDER_OBS

Type: Text
Width: 15

Defines term as order only, observation only, or both. A fourth category, Subset, is used for terms that are subsets of a panel but do not represent a package that is known to be orderable. We have defined them only to make it easier to maintain panels or other sets within the LOINC construct. This field reflects our best approximation of the terms intended use; it is not to be considered normative or a binding resolution.

HL7_FIELD_SUBFIELD_ID

Type: Text
Width: 50

A value in this field means that the content should be delivered in the named field/subfield of the HL7 message. When NULL, the data for this data element should be sent in an OBX segment with this LOINC code stored in OBX-3 and with the value in the OBX-5.

EXTERNAL_COPYRIGHT_NOTICE

Type: Memo
Width: N/A

External copyright holders copyright notice for this LOINC code

EXAMPLE_UNITS

Type: Text
Width: 255

This field is populated with a combination of submitters units and units that people have sent us. Its purpose is to show users representative, but not necessarily recommended, units in which data could be sent for this term.

LONG_COMMON_NAME

Type: Text
Width: 255

This field contains the LOINC name in a more readable format than the fully specified name. The long common names have been created via a tabledriven algorithmic process. Most abbreviations and acronyms that are used in the LOINC database have been fully spelled out in English.

EXAMPLE_UCUM_UNITS

Type: Text
Width: 255

The Unified Code for Units of Measure (UCUM) is a code system intended to include all units of measures being contemporarily used in international science, engineering, and business. (www.unitsofmeasure.org) This field contains example units of measures for this term expressed as UCUM units.

STATUS_REASON

Type: Text
Width: 9

Classification of the reason for concept status. This field will be Null for ACTIVE concepts, and optionally populated for terms in other status where the reason is clear.

DEPRECATED or DISCOURAGED terms may take values of: AMBIGUOUS, DUPLICATE, or ERRONEOUS.

STATUS_TEXT

Type: Memo
Width: N/A

Explanation of concept status in narrative text. This field will be Null for ACTIVE concepts, and optionally populated for terms in other status.

CHANGE_REASON_PUBLIC

Type: Memo
Width: N/A

Detailed explanation about special changes to the term over time.

COMMON_TEST_RANK

Type: Number
Width: N/A

Ranking by frequency of usage of approximately 20,000 LOINCs codes as reported in the U.S.

COMMON_ORDER_RANK

Type: Number
Width: N/A

Ranking of approximately 300 common orders performed by laboratories in USA.

HL7_ATTACHMENT_STRUCTURE

Type: Text
Width: 15

This field will be populated in collaboration with the HL7 Attachments Work Group as described in the HL7 Attachment Specification: Supplement to Consolidated CDA Templated Guide. As of Version 2.58, the text will either be "IG exists" (previously STRUCTURED) or "No IG exists" (previously UNSTRUCTURED) for relevant terms. The "IG exists" terms are those that have clinically-relevant HL7 implementation guides that use the U.S. Realm Header. The "No IG exists" terms are those approved by the HL7 Attachments WG for transmission using the Unstructured Document template of the C-CDA.

EXTERNAL_COPYRIGHT_LINK

Type: Text
Width: 255

For terms that have a third party copyright, this field is populated with the COPYRIGHT_ID from the Source Organization table (see below). It links an external copyright statement to a term.

PanelType

Type: Text
Width: 50

Describes a panel as a "Convenience group", "Organizer", or "Panel".

A "Panel" is an enumerated set of terms that are used together in direct clinical care. The package would typically be thought of as a single orderable item that contains a set of reported observations.

A "Convenience group" is an enumerated set of terms used for a common purpose, but not typically orderable as a single unit.

An "Organizer" is a subpanel (i.e., a child) within another panel that is only used to group together a set of terms, but is not an independently used entity. They often represent a header in a form, or serve as a navigation concept.

AskAtOrderEntry

Type: Text
Width: 255

A multi-valued, semicolon delimited list of LOINC codes that represent optional Ask at Order Entry (AOE) observations for a clinical observation or laboratory test. A LOINC term in this field may represent a single AOE observation or a panel containing several AOE observations.

AssociatedObservations

Type: Text
Width: 255

A multi-valued, semicolon delimited list of LOINC codes that represent optional associated observation(s) for a clinical observation or laboratory test. A LOINC term in this field may represent a single associated observation or panel containing several associated observations.

VersionFirstReleased

Type: Text
Width: 255

The LOINC version number in which the record was first released.

ValidHL7AttachmentRequest

Type: Text
Width: 50

A value of 'Y' in this field indicates that this LOINC code can be sent by a payer as part of an HL7 attachment request for additional information.

DisplayName

Type: Text
Width: 255

This field contains a name that is more "clinician-friendly" compared to the current LOINC Short Name, Long Common Name, and Fully Specified Name. It is created algorithmically from the manually crafted display text for each Part and is generally more concise than the Long Common Name.

MapTo Table Structure

LOINC

Type: Text
Width: 10

The deprecated term to which the replacement term(s) apply.

MAP_TO

Type: Text
Width: 10

A replacement term that is to be used in place of the deprecated or discouraged term.

COMMENT

Type: Memo
Width: N/A

Narrative text that explains the rational for using the recommended replacement term.

SourceOrganization Table Structure

ID

Type: Number
Width: N/A

A unique numeric identifier for the source. This identifier does not have any meaning outside of LOINC.

COPYRIGHT_ID

Type: Text
Width: 255

Used in the LOINC table as a foreign key.

NAME

Type: Text
Width: 255

Name of the organization or institution.

COPYRIGHT

Type: Memo
Width: N/A

Copyright notice to be displayed for the organization or institution.

TERMS_OF_USE

Type: Memo
Width: N/A

Terms of use text for an external source.

URL

Type: Text
Width: 255

URL link to the reference.