NPU definition, structure and presentation
Scope |
NPU definition encompasses essential information about an examination or a measurement. The syntax of a NPU definition comprises of a unique identifier, patient system, component, kind-of-property and measurement unit. |
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Syntax |
Note 1: The question mark indicates the placeholder for the result value. Note 2: The specifications in each string have the purpose to specify the description of the main strings when necessary. |
By word |
The NPU definition can be converted to a sentence: The kind-of-property of component B in a patient’s system 1 is [?] measurement unit Note 1: Component B is any object of interest and a part of system 1 Note 2: System 1 is any part, surroundings of a patient or a patient, comprising of component B and matrix |
By mathematical equation |
Note: This will appear for NPU definitions that belong to the rational, difference, logarithmic result type |
Example |
Definition by word: The mass concentration of Haemoglobin in a patient’s blood is [?] g/L Definition by mathematical equation |
Reference |
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Expressions |
NPU definition can be expressed in several ways. In order to make NPU definition understandable for clinicians and patients, a trivial name is often attached to a NPU definition. Trivial names may neither be unique or contain all information of the quantity. It is recommended to have a regulated system of trivial names governed by a central organisation in order to avoid misunderstandings. Long version: NPU28309 Blood-Haemoglobin; mass concentration= ? g/L Trivial name: E.g. Hemoglobin test Abbreviation: E.g.Hb Note 1: A trivial name is less technical and more recognizable than a NPU definition that is more technical. A national trivial name may be attached to the national prefered term. Note 2: The trivial name and abbrevation may also be used for a different NPU definition, e.g. NPUxxxxx Blood-Haemoglobin; subst. c.= ? mmol/L Note 3: There is no official trivial name for NPU definitions but may be regulated by each national society or governmental body |
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Concepts |
The concepts in the NPU definition are defined and traceable to international terminology, ontology or nomenclature (see Principles of terminology and Medical and metrological vocabulary) |
Language |
The lingua franca in NPU terminology is British English. Each country may translate NPU definitions into the country’s official language |
Number of characters |
There is no limit of characters in the NPU code. However, the length of the NPU code should be limited to the extent of readability and understandability |
Characters |
Some characters and signs appear in NPU definitions. Their definitions are:
Note: The result can differentiate between DNA from Streptococcus and Enterococcus
Note: The result cannot differentiate between DNA from Cryptococcus neoformans+Cryptococcus gattii species complex
Example: NPU29141 Urine—2–ethyl–5-methyl-3,3-diphenylpyrroline; arbitrary concentration(procedure) = ?
Example: NPU10444 Urine—17-Hydroxycorticosteroid; amount-of-substance(0-1 day after challenge) = ? µmol
Example: NPU03815 Extracellular fluid—Base excess; substance concentration(actual–norm) = ? mmol/L
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Reference |
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Principles |
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Examples of principle 1 |
A NPU definition may become obsolete, if:
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Examples of principle 2 |
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Examples of principle 3 |
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Reference |
Synonym |
Serial number, code |
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Scope |
A unique NPU definition can be identified by one unique identifier, national or international |
International unique identifier |
The International unique identifier consists of three letter abbreviation, NPU (Nomenclature on Properties and Units) and 5 digits The identifier indicates that the NPU definition can be used in any country Example: NPU02319 Blood—Haemoglobin(Fe); substance concentration = ? mmol/L |
National unique identifier |
The national unique identifier consists of three letter country code, according to ISO 3166-1, and 5 digits. Examples:
Note: National codes can have same digits, e.g. DNK12345, NOR12345 and SWE12345, but have different definitions. |
Reference |
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