Last Updated: 10-03-2020 15:48
Within the frame of the HBM4EU project, an EQUAS study was organised on the determination of two DINCH biomarkers in urine. This was the fourth ICI/EQUAS round for this substance group within the HBM4EU program. In total 12 laboratories were invited for this second round, of which 11 laboratories registered. Results were received from all 11 laboratories, located in 9 EU countries and the USA. In November 2019, each participant received two burdened control materials of human urine, A and B (single tube each), containing DINCH biomarkers in the range 5-15 ng/ml. Homogeneity assessment showed that both materials were sufficiently homogeneous for ICI/EQUAS testing. Previously conducted stability tests had shown that the biomarkers are stable when stored in the freezer and no significant loss of the biomarkers occurred during the course of the EQUAS test. 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 both biomarkers in both test materials. Two laboratories reported only one of the two biomarkers, all others determined both. The percentage of satisfactory Z-scores was around 90% for both biomarkers when including the results from the expert laboratories.