General Information on Reference Materials (QCMs)

The accuracy of chemical measurements, and thus the reliability of analytical data, becomes crucial when decisions about public or environmental health are based on this response.
Analytical laboratories have many tools available to evaluate and improve their analytical quality performance, and therefore the reliability and comparability of their results. One of the most effective is the use of certified and not certified reference materials (RM).

High homogeneity and stability over time of the analytes are essential characteristics of reference materials, both certified and not. Furthermore, in both cases, their preparation must meet specific quality criteria. Depending on the current state of the art, in case of certified RM, the concentration of analytes of interest is known with the lowest uncertainty and the highest possible accuracy.

Reference materials are distinguished primarily for their use. Certified Reference materials are mainly used for method validation and for the evaluation of accuracy and uncertainty (according to the holistic approach); not-certified reference materials are mainly used for the evaluation of the long term reproducibility (through the establishment of control charts) and the comparability of data through participation in Proficiency Testing (PT) schemes.

Not Certified Reference Materials may also be called “Quality Control Materials” or QCMs. Not certified reference materials used in proficiency testing exercises are fully characterized in terms of matrix and homogeneity/stability of the analytes; furthermore, these materials, having been analyzed in PT exercises, are also characterized by a “consensus value” for the analytes.

Although QCMs have not been subjected to a full certification process (which requires a huge commitment of time and cost) they may be used for external control of analytical performance of a laboratory by comparing its analytical results with the “consensus value” obtained from the population of laboratories that analyzed the same material in a previous PT exercise.

Reference materials (QCM) tested in the QC Proficiency Testing Programme organized by Quality Consult represent an optimal choice for both the construction and maintenance of control charts, external control and for any corrective action.