Last Updated: 17-10-2019 11:26
Within the frame of the HBM4EU project, an External Quality Assurance Scheme (EQUAS) was organised on the determination of four OPFR biomarkers in urine. This was the 3rd ICI/EQUAS round for this substance group within the HBM4EU program.
In total, 14 laboratories were invited for this 3rd ICI/EQUAS and only five laboratories (including three expert laboratories) submitted results. The number of OPFRs covered by the different laboratories varied widely from two to all four target biomarkers.
In June 2019, each participant received one tube of burdened control materials of human urine (low level – level 1), one tube of burdened control materials of human urine (high level – level 2) and one tube of “blank” urine (non-spiked). The biomarker concentrations were approximately in the range of 1-5 µg/L and 7-20 µg/L for level 1 and level 2, respectively. The concentrations were chosen according to the review of relevant data on the occurrence of OPFRs in urine of the European population published mostly during the last five years.
A homogeneity assessment showed that both materials were sufficiently homogeneous for EQUAS testing. No issues with stability of testing materials occurred for OPFRs.
The determination of expert value based on results from expert laboratories was possible only for DPHP. The uncertainty of the expert-derived mean for BDClPP was too high to be used as assigned value. For BClPP and BCEP the minimum number of expert results was not reached.
Due to a limited number of obtained results, evaluation of laboratory performance using Z-scores could only be performed for DPHP. The achieved results for BDClPP, BDClPP and BCEP are present in the report for further comparison between participants and expert labs.