Introduction to the National code list of laboratory items (NČLP in Czech)
When ordering or communicating measured or observed results, clinical laboratories have to clearly define the quantity to which a value (a result of measurement or observation) is assigned. In this sense, the term ‘quantity’ is meant to indicate a particular characteristic that always involves information about the measured system and component. A component is the subject of a measurement or observation (for example glucose as an analyte, erythrocyte as a cell, synthesis as property, etc.). A system is a bounded part of a universe, where a particular component can be found (for example environment, patient, blood, plasma, or urine). The third determining characteristic is a kind-of-property (for example weight, length, substance concentration, compatibility, or presence). Kind-of-property determines the unit of measurement (for example kg, meter, mol/L, katal/L, and their multiples). A type of procedure complements a more detailed specification of a quantity (absorption spectrophotometry, microscopy, FPIA, etc.). These five terms make up the conceptual basics of the NČLP. Individual laboratory items are defined by assembling the five above-mentioned elements from predefined building blocks stored in relevant code lists. Such assembly of five terms is assigned a unique NČLP key.
The National code list of laboratory items is used mainly by clinical laboratories with a focus on clinical biochemistry, clinical haematology, clinical immunology, nuclear medicine (in vitro methods), laboratory part of transfusion medicine, clinical microbiology, serology, and the like. NČLP is used for requesting laboratory tests, communicating their results, working with laboratory tests, archiving laboratory data, and also other activities where appropriate. Healthcare information systems use it mainly to define items determined not only by clinical laboratories but by paraclinical fields in general. It can be further used for data transfers within the Data standard and to communicate patient data between information systems of healthcare facilities (in sense of the methodological instructions of the Ministry of Health).
At the national level, the NČLP is maintained centrally in cooperation with the Ministry of Health. This way ensures a connection to a corresponding version of “Data standard for the transfer of patient data between information systems of healthcare facilities”.
Locally, the application is provided by an authorised laboratory specialist who, for every measured (and communicated) laboratory item, selects a corresponding counterpart from NČLP and thus ensures an unambiguous mapping (including the addition of other necessary information).
The mapping method depends on a particular laboratory information system. Due to the highly professional nature of mapping, it is not recommended to entrust the task to employees of external organisations (providing for example maintenance of the laboratory information system). Correct mapping creates a basis for electronic communication between information systems and it is directly related to the issue of “good laboratory practice”.