Last Updated: 05-02-2019 12:58
Within the frame of the HBM4EU project, an ICI was organised on the determination of 15 phthalate biomarkers in urine. In total 18 laboratories from 13 countries registered and submitted results. In June 2018, two control materials of human urine were sent (at concentrations in the range 1-10 μg/L and 4-40 μg/L). Homogeneity and stability were tested. In total, 19 consensus values and Z-scores could be calculated. The ICI-RSDR varied from 17% to 42%, exceeding the FFP-RSD of 25% in most cases. For MnPeP (sample B), and OH-MiNP, cx-MiNP, OH-MiDP, cx-MiDP in both test samples, no assigned value and Z-scores could be determined due to a too high variability in the results reported by the labs, or too few results. The percentage of acceptable Z-scores obtained for each biomarker ranged from 71% for 5cx-MEPP in sample B (36 μg/L), to 94% for MBzP and MiBP (4-7 μg/L), and was around 80% in most other cases. Out of the 18 labs, 9 demonstrated good overall performance by obtaining satisfactory Z-scores (in ≥95% of the cases) for all biomarkers. The number of phthalate biomarkers covered by the different laboratories varied widely: from 3 to all 15 target biomarkers. Overall, 4 out of 18 labs were capable to provide good quantitative results for all 15 biomarkers. While several biomarkers (MBzP, MiBP, MnBP, MEHP, 5OH-MEHP and 5oxo-MEHP) can be satisfactory determined by around 80% of the labs, improvement in both scope and quantitative performance is required.