Last Updated: 17-10-2019 11:00
Within the framework of the HBM4EU project, an External Quality Assurance Scheme (EQUAS) was organized and conducted for the analysis of cadmium in blood.
The study was performed from October 2018 to January 2019.
The HBM4EU QAU selected six expert laboratories for cadmium in blood. 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, 58 laboratories were invited for this second round, of which 35 laboratories from 22 countries registered.
The participation in this EQUAS was satisfactory; 33 out of 35 laboratories (94%) submitted their results.
In November 2018, six different test samples consisting of 3 mL blood spiked with cadmium at two different concentrations (Cdlow, Cdhigh), three of each concentration, were prepared, and three samples of each concentration were sent to the participating expert and candidate laboratories for 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 67% of the results were satisfactory, 12% were questionable and 7% were unsatisfactory (Table 1). The evaluation of Cdhigh showed that 91% of the results were satisfactory, 6% were questionable and 3% were unsatisfactory.