Logical Observation Identifiers Names and Codes

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LOINC is a common language (set of identifiers, names, and codes) for clinical and laboratory observations.


LOINC is a rich catalog of measurements, including laboratory tests, clinical measures like vital signs and anthropomorphic measures, standardized survey instruments, and more. LOINC enables the exchange and aggregation of clinical results for care delivery, outcomes management, and research by providing a set of universal codes and structured names to unambiguously identify things you can measure or observe.

Put another way, LOINC provides the lingua franca for interoperable data exchange.

Today, it contains concepts for everything from a serum alpha 1 antitrypsin level to a zygomatic arch x-ray report. For each concept, LOINC contains many other rich details, such as synonyms, units of measure, and carefully crafted descriptions.

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LOINC, Identifiers Names, Identifiers Codes, Information Systems, LOINC Identifier, LOINC Observation

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Information Systems LOINC Terminologies, LOINC Identifier Terminologies, LOINC Observation System Terminologies, LOINC

LOINC_NumThe unique LOINC Code is a string in the format of nnnnnnnn-n.string-
ComponentFirst major axis-component or analyte.string-
PropertySecond major axis-property observed (e.g., mass vs. substance).string-
Time_AspctThird major axis-timing of the measurement (e.g., point in time vs 24 hours)string-
SystemFourth major axis-type of specimen or system (e.g., serum vs urine).string-
Scale_TypFifth major axis-scale of measurement (e.g., qualitative vs. quantitative)string-
Method_TypSixth major axis-method of measurementstring-
ClassAn arbitrary classification of the terms for grouping related observations together. The current classifications are listed in Table 32. 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.string-
Version_Last_ChangedThe LOINC version number in which the record has last changed. For new records, this field contains the same value as the loinc.FirstPublishedRelease field.string-
Chng_TypeChange Type Codestring-
Definition_DescriptionNarrative 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.string-
StatusACTIVE = Concept is active. Use at will.string-
Consumer_NameAn experimental (beta) consumer friendly name for this item. The intent is to provide a test name that health care consumers will recognize; it will be similar to the names that might appear on a lab report and is not guaranteed to be unique because some elements of the LOINC name are likely to be omitted. We will continue to modify these names in future release, so do not expect it to be stable (or perfect).string-
Class_TypeLeve: Nominalinteger-
FormulaContains 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.string-
SpeciesCodes detailing which non-human species the term applies to. If blank, “human” is assumed.string-
Exmpl_AnswersFor some tests and measurements, we have supplied examples of valid answers, such as “1:64”, “negative @ 1:16”, or “55”.string-
Survey_Quest_TextVerbatim question from the survey instrumentstring-
Survey_Quest_SrcExact name of the survey instrument and the item/question numberstring-
Is_Units_Required"true" & "false" field that indicates that units are required when this LOINC is included as an OBX segment in a HIPAA attachmentboolean-
Related_Names_2This 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). It replaces #8, Relat_NMS.string-
Short_NameIntroduced 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.string-
Order_ObsDefines 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.string-
Is_CDISC_Common_Tests“true” in this field means that the term is a part of subset of terms used by CDISC in clinical trials.boolean-
HL7_Field_Subfield_IDA 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.string-
External_Copyright_NoticeExternal copyright holders copyright notice for this LOINC code.string-
Example_UnitsThis 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.string-
Long_Common_NameThis field contains the LOINC name in a more readable format than the fully specified name. The long common names have been created via a table driven algorithmic process. Most abbreviations and acronyms that are used in the LOINC database have been fully spelled out in English.string-
Document_SectionClassification of whether this LOINC code can be used a full document, a section of a document, or both. This field was created in the context of HL7 CDA messaging, and populated in collaboration with the HL7 Structured Documents Work Group.string-
Example_UCUM_UnitsThe 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.string-
Example_SI_UCUM_UnitsThe 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 SI UCUM units.string-
Status_ReasonClassification 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.string-
Status_TextExplanation of concept status in narrative text. This field will be Null for ACTIVE concepts, and optionally populated for terms in other status.string-
Change_Reason_PublicDetailed explanation about special changes to the term over time.string-
Common_Test_RankRanking of approximately 2000 common tests performed by laboratories in USA.integerlevel : Ordinal
Common_Order_RankRanking of approximately 300 common orders performed by laboratories in USA.integerlevel : Ordinal
Common_SI_Test_RankCorresponding SI terms for 2000 common tests performed by laboratories in USA.integerlevel : Ordinal
HL7_Attachment_StructureThis 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. Text will either be STRUCTURED or UNSTRUCTURED for relevant terms.string-
External_Copyright_LinkFor terms that have a third party copyright, this field is populated with the COPYRIGHT_ID from the Source Organization table. It links a external copyright statement to a term.string-
Panel_TypeDescribes 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.string-
Ask_At_Order_EntryA multivalued field, 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.string-
Associated_ObservationsA 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.string-
54532-7Cancer-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSCancer000Panel
54543-4Vision-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSVision000Panel
54571-5Dental-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSDental000Panel
54511-1Behavior-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSBehavior000Panel
54537-6Metabolic-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSMetabolic000Panel
54536-8Infections-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSInfections000Panel
55042-6Restraints-Pt^Patient-SURVEY.MDS2.27MINACTIVE4falsePoint in time; Random; Survey; SURVEY.MDSRestraints000Panel
26438-2Cytology studiesCmplx-^PatientSetATTACH.LAB2MINACTIVE3ATTACH; ATTACH.LAB; Complex; LabCytology studies (set)000
18716-1Allergy studiesCmplx-^PatientSetATTACH.LAB2.27MINACTIVE3ATTACH; ATTACH.LAB; Complex; LabAllergy studies (set)000
32624-9RaceTypePt^PatientNomCLIN2.4MINACTIVE2falseCLIN; Ethnicity; Nominal; Point in time; Random; TypRacePID-10Race000