Last Updated: 17-10-2019 11:28
Within the framework of the HBM4EU project, an External Quality Assurance Scheme (EQUAS) was organized and conducted for the analysis of per- and polyfluoroalkyl substances (PFAS) in serum. PFAS correspond to 12 biomarkers: PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFBS, PFHxS, PFHpS, PFOS.
The study was performed from May 2019 to July 2019.
In total, 26 laboratories were invited for this third round, of which 20 laboratories from 12 countries registered.
The participation in this EQUAS was satisfactory; 20 out of 20 laboratories (100%) submitted their results.
In June 2019, 12 different test samples consisting of 5 mL serum spiked with PFAS at two different concentrations (PFASlow, PFAShigh), 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.
The HBM4EU QAU had selected six expert laboratories for PFAS in serum. Four expert laboratories were from Europe (HBM4EU consortium) and also participated as candidates. Two expert laboratories were from outside Europe (Japan, Canada).
Homogeneity assessment of the control materials confirmed that the materials were adequately homogeneous. The stability test demonstrated no significant loss of the biomarkers in the course of this EQUAS.
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%. Assigned values and Z-scores could be determined for all biomarkers at the low level and for all biomarkers at the high level.
The percentage of satisfactory Z-scores obtained for each biomarker ranges from 75% (PFHpSlow) to 100% (PFDAlow, PFHxShigh).