LOINC Term Basics

LOINC's goal is to create different codes for each test, measurement, or observation that has a clinically different meaning. To do that LOINC codes distinguish a given observation (test ordered/reported, survey question, clinical document) across six dimensions that we call Parts.

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LOINC Parts

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Component (Analyte)

The substance or entity being measured or observed.

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Property

The characteristic or attribute of the analyte.

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Time

The interval of time over which an observation was made.

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System (Specimen)

The specimen or thing upon which the observation was made.

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Scale

How the observation value is quantified or expressed: quantitative, ordinal, nominal.

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Method

OPTIONAL A high-level classification of how the observation was made. Only needed when the technique affects the clinical interpretation of the results.

Example LOINC

Here is a breakdown of the LOINC for a manual count of white blood cells in cerebral spinal fluid specimen, which is represented by LOINC code 806-0:

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Component (Analyte)

Leukocytes (white blood cells)

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Property

NCnc (Number concentration)

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Time

Pt (Point in time)

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System (Specimen)

CSF (Cerebral spinal fluid)

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Scale

Qn (Quantitative)

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Method

Manual Count

LOINC Names

LOINC creates several different text labels (names) to represent each concept. We call the six-part formal name, as described above, the Fully-Specified Name (FSN). We also create a more clinician-friendly display called the Long Common Name (LCN) and a Short Name that can be handy when you need a column header in a report. Here are the names for LOINC code 806-0:

Fully-Specified Name (FSN)

Leukocytes: NCnc: Pt: CSF: Qn: Manual count

Long Common Name (LCN)

Leukocytes [#/volume] in Cerebral spinal fluid by Manual count

Short Name

WBC # CSF Manual