One of the important conceptual foundations in the field of standardisation of laboratory fields is the National code list of laboratory items (NČLP in Czech), introduced in 1997 by the methodological instructions of the Ministry of Health of the Czech Republic (see Bulletin of Ministry of Health CR, volume 1997, issue 7, July 1997, pages 2 to 4) and declared in an innovated form in connection with the Data standard DS 2.01.01 (and higher) in 2002 (see National code list of laboratory items) and with the Data standard DS 3.01.01 (and higher) in 2003. The Bulletin of Ministry of Health CR, 2015, issue 20, declared further development of NČLP in connection with the Data standard series 4 (development and maintenance of DS3 was brought to an end). 

The NČLP is based on the IUPA/IFCC nomenclature for creating NPU codes. In the beginning, the basis for the NČLP and the NPU were similar (NPU codes were not originally intended to be used as a code list in contrast to NČLP that was meant to purely serve this purpose), but a gradual development lead, in some cases, to different constructions.

The NČLP is continuously expanded in the mutual cooperation of leading experts from societies of clinical fields with laboratory component of the Czech Medical Association (CzMA) and the Czech Society of Medical Informatics and Scientific Information CzMA and the Ministry of Health CR. Its current version can be found on or on web services of the Ministry of Health CR. 

In practice, the NČLP is used mainly by the Data Standard of the Ministry of Health of Czech Rep. (DASTA), laboratory information systems (LIS), some hospital information systems (NIS), and it is expected to be used by more sophisticated information systems of general practitioners (ISPL). The NČLP is further used when creating standards in laboratory and clinical fields, within the EQA control systems, in the process of creating encyclopedias of laboratory fields, texts of repetitoria used in education, etc. 

The NČLP is continuously expanded, modified, and improved, especially concerning creating standards in laboratory and clinical fields.


The National code list of laboratory items

From the informatics point of view, the national code list of laboratory items (NČLP in Czech) is a data file containing basic definitions and descriptions of laboratory items to the extent necessary for the Data Standard of the Ministry of Health CR and routine laboratory practice. The NČLP further contains basic definitions and information necessary to create standards of effective medical care and to create standards of quality management in clinical laboratories. See [NCLPPOL].

It is further necessary for many healthcare information systems (LIS, NIS, ISPL).

It is made up using elements stored in internal code lists.

The above-mentioned mainly include code lists of systems, components, procedures, kind-of-properties, and units. 


A system is a bounded arrangement of a set of elements and a set of relationships between these elements. It is a subject of a laboratory test (biological material; e.g. plasma). See the systems code list - [NCLPSYST].

A component is a definable part of a system. It is a measured quantity itself (e.g. glucose). See the components code list – [NCLPKOMP].

Kind-of-property is a characteristic of a component (subject) that can be quantitatively differentiated and qualitatively determined (e.g. amount of substance, length, colour). See the kind-of-properties code list - [NCLPDRVL] and NČLP: Kind-of-properties.

A unit is a quantity accepted by a convention for a quantitative comparison of the same kind of quantities. It is closely related to kind-of-property. See the kind-of-properties and units code list - [NCLPJEDN] and SI units.

A procedure is a laboratory examination procedure used to obtain characteristics of components and their possible quantitative comparison. See the procedures code list - [NCLPPROC].

A key is assigned to every laboratory item. It is a five-character (a positive integer) unambiguous element used primarily by computer information systems and the data standard to unequivocally identify an item.

A laboratory item is a quantity defined in NČLP using the five above mentioned principal elements (system, component, kind-of-property, unit, and procedure).

This five-element definition has always assigned a unique identification key, which is considered a part of the basic item's definition. 

The basic definition of a laboratory item has other data appended – the ones necessary for information systems, data standard, standards of effective healthcare, and standards of quality management in clinical laboratories. These include, in particular, a name of the laboratory item, a component class, a gestion, an item type in terms of a dialog, an origin, a value format, and other. For each item, links to a range of other mandatory or optional information are available. 


Construction of a laboratory item is based on the SKDJ and procedures code lists.

The SKDJ code list is generated from components, systems, kind-of-properties, and units code lists.

Kind-of-properties code list is connected to the units code list.

This is how an author creating a new NČLP item proceeds. An average user does not need to know about the existence of the SKDJ code list.

The SKDJ code list is important for information systems as relevant links to corresponding IFCC, IUPAC, and other code lists are made through it. 


A local code list of laboratory items is intended for particular laboratory users.

Based on a National code list of laboratory items (NČLP) there are local code lists of laboratory items (LČLP) generated. They are a subset of NČLP and have clearly defined rules for their generation and mutual relations. LČLP respect the needs of specific laboratories. See [LCLPPOL].

A local code list of laboratory items is always generated in a direct connection to a specific suitable NČLP item. Thus all data associated with the NČLP item are also available for the corresponding LČLP item. LČLP items have other necessary data of local character attached.

For a correct realization of these connections there exists a user version of an information system SLP as well as a user version of ČLP software (its distribution is carried out by the Ministry of Health CR since 2001 and can be found at, derived from a reference author's version of SLP information system (of which it is a subset).

Detailed descriptions of the procedures for creating links between NČLP and LČLP can be found in ČLP software and SLP information system together with suitable tools for adding other data.


The name of the NČLP laboratory item is constructed using individual elements:

      a name of the component (up to 55 characters),

      abbreviated name of the system (code or text up to 32 characters),

      abbreviated name of the kind-of-property (code or text up to 24 characters),

      unit (up to 20 characters)

      abbreviated name of the procedure (code or text up to 32 characters)


In practice, the length does not exceed 120 characters.

The notation structure is as follows:

Component (system; kind-of-property [unit] procedure)


Characters “ ( ; [ ] ) “ are inserted automatically when the name is created – individual texts are taken from the corresponding code lists. Characters “ ( ) “ can also be found in the name of the component or the name of the system.

The above-mentioned structure is the basic name of the laboratory item. It should be used in this way to unambiguously identify the item.

An abbreviated variant is also possible – it does not characterise the procedure. It is suitable when there is no need to emphasize the procedure. 

Component (system; kind-of-property [unit]*)


Component (system; kind-of-property [unit])

Both notations are equivalent in their use. 

Names of the laboratory item are also accompanied by their synonyms. Synonyms are not intended for ordinary use in documents concerning standards of effective healthcare or quality management in clinical laboratories. They only serve to provide links to older or other technical texts.

A special type of synonyms includes a chemical name according to IUPAC (for some, mostly biochemical, items).

Component classes make it possible to classify the item into one or more groups (e.g. 'proteins', 'enzymes', 'tumor markers'). They are used for searching, grouping in search lists, and further processing of items for the needs of encyclopedias and lists. The relevant classes can be assigned to an item by choosing from the code list of components - [NCLPTK]. The main class is stored in the category item and can be used to create search lists.

Gestion states for which of the professional societies of the Czech Medical Association of J. E. Purkyně the definition was created by an author. The information is only indicative.

See the gestion code list - [NCLPTNG].


Variants for electronic ordering of examination (marked as “DS” in the NČLP dialog) make it possible to indicate whether an item can be used for electronic ordering of examination and which variant can be selected. 

See the code list of variants for electronic ordering of examination - [NCLPVEOV]. 

Item type in terms of a dialog is assigned from a corresponding code list of item types in terms of a dialog. Every NČLP item has one such item type assigned.

The basic item types include 'numerical', 'text formalized', 'text non-formalized', and 'structured' (for microbiological findings, search lists, and special structures). Text formalized item types have assigned links to corresponding text result matrices (MTVs). Numerical item types have assigned information concerning numerical range, display format, and possibly also optional data on reference intervals. Definitions of the structures are available for structured item types.

See types of NČLP items in terms of a dialog in [NCLPTYPD] code list.


Value format is directly connected with item type in terms of a dialog. It defines the form and the display format of the value of the corresponding item. See the value format code list. Every NČLP item has assigned one value format. It is, among other things, used to derive specific data blocks enabling the communication of the results ('Vri' data blocks).

See types of NČLP items in terms of value format in [NCLPFH] code list.


A format of the reference intervals is connected both to the item type in terms of a dialog and the value format. It defines whether the reference intervals are displayed for the item and if yes it determines the display format. It has meaning for numerical items. See the format of the reference intervals code list - [NCLPFRM].


MTVs are the so-called “text result matrices”. These are predefined unambiguous sets of texts used for formalized communication of results in a text form.

They are used to communicate values of items that have text as a result of examination (e.g. colour, shape, predefined list of characteristics or attributes, etc.). MTVs are also used to communicate substitutes of item values where there is not possible to fully determine the result due to a collision (e.g. collision state of the material, atypical situation, etc.). See MTV code list - [NCLPMTV].


Origin is a special type designation of a laboratory item with regard to a form in which the item is created or with regard to its further processing and use. See types of items in terms of their origin code list.

Due to the importance of this information for the creation of standards, the code list of origins is further elaborated.

See types of the NČLP items in terms of origin, description in [NCLPVZNK] code list.


The relationship in NČLP and LČLP between the type of items in terms of origin and the type of items in terms of a dialog.

See relationships in the item description in NČLP, LČLP, and "VR".



There are many connections and relations between the NČLP items themselves and the NČLP items and other code lists and files. They are not only important for DS, but also information systems, laboratory technologies, clinical interpretations, many other standards, and possibly also for SOP documents and others.

To describe the relationships, there exist other code lists as an optional part of the NČLP.

For more information see:

relations between items and with items - general 

relations between NČLP items - general 

relations between NČLP items - definitions