Metrological traceability – a concept for standardization in laboratory medicine

Abstract

Abstract:The concept of measurement traceability provides the most important strategy in achieving standardization in laboratory medicine aimed at equivalent measurement results regardless of the principle of measurement, the method, the actual measurement procedure (test kit) and the laboratory where analyses are carried out.Keywords: measurement traceability; reference materials; reference measurement procedures; reference measurement services; standardization. forms the basis for standardization in laboratory medicine which is described in detail in ISO 17511 [ 2 ]. The strategy of traceability in laboratory medicine is described in detail in ISO 17511 [ 2 ]. As demonstrated in Figure 1 , a result of measurement in a patient sample should be traceable along a cascade of mea surement procedures and calibrators/reference materials of increasing metrological order up to the highest level represented by the definition of the measurand in SI units.This hierarchical scheme represents a sequence of measurement procedures and materials of increasing metrological order -from the routine sample obtained from a patient applying the end-user ' s routine measurement procedure (test kit) -to the highest level: the definition of the measurand in SI units. The increasing uncertainty μ c (y) from the top level down to the result in a patient sample is symbolized by the horizontal bars.

Harmonization in laboratory medicine: the complete picture

“…According to the traceability strategy, a result of measurement in a patient sample should be traceable along a cascade of measurement procedures and calibrators/reference materials of increasing metrological order up to the highest level represented by the definition of the measurand in SI units [ 14 ]. In principle, if a reference system is in place for an analyte, its measurement is described as ' standardized ' , thus giving clinical laboratories the best possible opportunity to obtain analytical results close to true values, which are thus harmonized across different routine measurement procedures [ 12 ].…”

“…In particular, two working groups are providing a list of reference materials and reference procedures, and are identifying reference measurement laboratories [ 14 ]. However, the evaluation and validation of commercially available kits, even for high-order traceable assays, is still the duty and responsibility of laboratory professionals and cannot be ignored.…”

Harmonization in laboratory medicine: more than clinical chemistry?

“…As recently stated by Miller [7], the history of the awareness of the importance of standardization can be traced back to the seminal paper by Belk and Sunderman [8] who, in 1947, demonstrated wide discrepancies between results of 59 US hospital laboratories. The findings made in their survey paved the way for the development of external quality assurance (EQA)/proficiency testing (PT) programs and prompted efforts to establish the hierarchy of certified reference materials (CRMs) and reference measurement procedures (RPMs) that could be accepted as high-order references for the standardization of measurand results [9,10]. However, increasing consensus has been achieved on the need to focus on a global picture of harmonization, mainly in view of (a) the nature of errors in laboratory medicine [11]; (b) the evidence of large variations in terminology, units and reference intervals [12]; and (c) the risks for patient safety related to the above issues [1].…”

Progress towards standardization: an IFCC Scientific Division Perspective

“…This implies traceability to RMPs through an unbroken chain of steps, each contributing to the measurement uncertainty [ 2 ]. In addition, since the use of an agreed terminology is needed to ensure the correct reporting of results generated by specialists in Laboratory Medicine to clinicians, definition and update of metrological terms and units are major roles of the Joint Committee for Nomenclature, Properties and Units of the IFCC and The International Union of Pure and Applied Chemistry (IUPAC) (C-NPU) [ 3 ].…”