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Last Updated: 12-02-2020 9:56
Within the framework of the HBM4EU project, an External Quality Assurance Scheme (EQUAS) was organized and conducted for the analysis of cadmium in urine.
The study was performed from September 2019 to October 2019.
The HBM4EU QAU had selected six expert laboratories for cadmium in urine. Four expert laboratories were from Europe (HBM4EU consortium) and three of them also participated as candidates. Two expert laboratories were from outside Europe (Japan, USA).
In total, 56 laboratories were invited for this fourth round, of which 22 laboratories from 13 countries registered.
The participation in this EQUAS was successful; 20 out of 22 laboratories (91%) submitted their results.
In September 2019, twelve different test samples consisting of 5 mL urine spiked with cadmium at two different concentrations (Cdlow, Cdhigh), six of each concentration, were prepared and sent to the participating expert laboratories for analysis. Each candidate laboratory got two samples, one of each concentration for single analysis.
Homogeneity and stability assessment of the control materials confirmed that the materials were adequately homogeneous and stable.
The expert assigned values were calculated by averaging the values obtained by the expert labs.
The proficiency of the laboratories was assessed through Z-scores calculated using the mean concentration as established by expert laboratories as assigned value, and a fixed fit-for-purpose relative target standard deviation (FFP-RSDR) of 25%.
The evaluation of Cdlow showed that 90% of the results were satisfactory, 5% were questionable and 5% were unsatisfactory. The evaluation of Cdhigh showed that 95% of the results were satisfactory, none were questionable and 5% were unsatisfactory.
