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.
The substance or entity being measured or observed.
The characteristic or attribute of the analyte.
The interval of time over which an observation was made.
The specimen or thing upon which the observation was made.
How the observation value is quantified or expressed: quantitative, ordinal, nominal.
OPTIONAL A high-level classification of how the observation was made. Only needed when the technique affects the clinical interpretation of the results.
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:
Leukocytes (white blood cells)
NCnc (Number concentration)
Pt (Point in time)
CSF (Cerebral spinal fluid)
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
WBC # CSF Manual