Last Updated: 17-10-2019 11:09
Within the framework of the HBM4EU project, an External Quality Assurance Scheme (EQUAS) was organized and conducted for the analysis of Polycyclic Aromatic Hydrocarbon metabolites (PAH met.). PAH met. correspond to 13 biomarkers: 1-naphthol, 2-naphthol, 1,2-DHN, 2-FLUO, 3-FLUO, 9-FLUO, 1-PHEN, 2-PHEN, 3-PHEN, 4-PHEN, 9-PHEN, 1-PYR and 3-BaP in urine.
The study was performed from October 2018 to January 2019.
In total, 42 laboratories were invited for this second round, of which 27 laboratories from 13 countries registered.
The participation in this EQUAS was satisfactory; 27 out of the registered 27 laboratories (100%) submitted their results.
In November 2018, six different test samples consisting of 5 ml urine spiked with the biomarker at two different concentrations (PAH met.low and PAH met.high) were prepared and sent to the participating expert and candidate laboratories for analysis.
The HBM4EU QAU had selected six expert laboratories for PAH met. in urine. Four expert laboratories were from Europe (HBM4EU consortium) and also participated as candidates. Two expert laboratories were from outside Europe (Japan, USA).
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 seven biomarkers at the low level and for seven biomarkers at the high level.
For two biomarkers at the low level and for two biomarkers at the high level, Z-scores could only be determined using the consensus value of the ICI as described in SOP HBM4EU-SOP-QA-003.
The percentage of satisfactory Z-scores obtained for each biomarker ranges from 62% (1-PYRlow) to 100% (2-FLUOlow, 3-FLUOhigh, 1-PHENhigh and 2-PHENlow).
For four biomarkers (1,2-DHN, 9-FLUO, 9-PHEN and 3-BaP) no kind of Z-score could be provided.