HBM4EU ICI EQUAS report OPFR in urine round 1

Within the frame of the HBM4EU project, an Interlaboratory Comparison Investigation (ICI) was organised on the determination of four OPFR biomarkers in urine. In total 13 laboratories were invited for this first round, of which seven laboratories from six EU countries registered and five laboratories submitted results. In July 2018, each participant received three tubes for burdened control materials of human urine (low level – level 1), three tubes for burdened control materials of human urine (high level – level 2) and three tubes for “blank” urine (non spiked). The biomarker concentrations were mostly in the range 1-1.5 μg/L and 7.5-12 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 European population published mostly during last five years. A homogeneity assessment showed that both materials were sufficiently homogeneous for ICI testing. Some issues with stability of testing materials occurred for several OPFRs. The number of OPFRs covered by the different laboratories varied widely from one to all four target biomarkers. All participants reported results for DPHP and BDClPP. Three results for BClPP and one result for BCEP were submitted. Due to a limited number of obtained results, further evaluation of laboratory performance using Z-scores was not able to be perform. The achieved data are present in the report for further comparison between participants.