EN ISO 17511:2003 – In vitro diagnostic medical devices – Measurement of quantities in biological samples – Metrological traceability of values assigned to calibrators and control materials (ISO 17511:2003)

4.1.5 The value assigned to a measurement standard at a given level shall be associated with an uncertainty of measurement that shall include inherited consecutive uncertainty contributions from measurement standards and measurement procedures at all higher levels of the calibration hierarchy. NOTE The chosen measure of uncertainty preferably should be estimated according to the GUM (see clause 6).
4.1.6 To ensure the validity of a metrological traceability chain, the quantity shall be the same at all levels. The analytical specificities of the described routine procedure and metrologically higher reference measurement procedures as well as the stability and commutability of the calibrators shall be known or investigated. The outcome shall be described in the manufacturer’s technical documentation.
4.1.7 The responsibility of the manufacturer for describing the metrological traceability chain shall start at the value of the manufacturer’s product calibrator and end at the metrologically highest reference used by the manufacturer. The uncertainty of this reference shall include any further upwards contributions to uncertainty.
4.2 Structure and nomenclature
4.2.1 As the structure of an actual metrological traceability chain depends on the metrological possibilities, any description of the elements of the chain shall include or refer to definitions of terms and statements of the metrological properties of measuring systems and reference materials involved. NOTE 1 The series of measurement standards defined in VIM is based on the needs of calibration hierarchies for quantities in physics, such as a length, a time, a temperature, a pressure, an electrical potential difference (voltage), a volume, and an absorbance, and comprises – primary measurement standard,
– secondary measurement standard,
– reference measurement standard,
– working measurement standard. NOTE 2 For practical purposes – especially for quantities in chemistry
– there should be a distinction between the elements in the calibration hierarchy that are measuring systems, described in and operated according to a measurement procedure, and those that are used for calibration of the measuring systems. The latter type is called calibration material or calibrator.
In chemical measurement the concept “reference material” includes “calibration material” and “trueness control material”.
4.2.2 In a given calibration hierarchy providing metrological traceability to SI, the following concepts shall be identified as appropriate (see Figure 1), see also 4.2.3 and 4.2.4.
a) SI unit of measurement, whether base or derived, to which metrological traceability preferably shall refer, for example mole, kilogram, mole per cubic metre (= millimole per litre), gram per kilogram (= 10 ).
b) Primary reference measurement procedure shall be based on a principle of measurement proved to be analytically specific, providing metrological traceability to an SI unit of measurement without reference to a calibrator for the same quantity, and having a low uncertainty of measurement.
EN ISO 17511:2003 – In vitro diagnostic medical devices – Measurement of quantities in biological samples – Metrological traceability of values assigned to calibrators and control materials (ISO 17511:2003)