RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays

Area of Science:

• Radiation dosimetry and biodosimetry
• Medical management of radiation exposure
• Inter-laboratory comparisons

Background:

• Accurate radiation dose estimation is critical for managing victims of radiological or nuclear incidents.
• Biological and physical dosimetry assays are used to reconstruct radiation exposure.
• Regular validation through inter-laboratory comparisons (ILCs) ensures the quality and reliability of these assays.

Purpose of the Study:

• To evaluate the performance of various cytogenetic, molecular, and physical dosimetry assays in an inter-laboratory comparison (ILC) setting.
• To assess the accuracy of dose estimations for identifying clinically relevant exposure groups.
• To identify potential research needs and technical challenges in radiation dose reconstruction.

Main Methods:

• Three blinded samples (blood, enamel, mobile) were exposed to reference X-ray doses (0, 1.2, 3.5 Gy).
• 86 specialized teams from 46 organizations across 27 nations participated, using assays like DCA, CBMN, FISH, PCC, gH2AX, GE, EPR, and LUM.
• Dose estimates were analyzed based on categorization into clinically relevant groups, triage uncertainty intervals, and absolute differences from reference doses.

Main Results:

• Most assays successfully categorized unexposed and highly exposed individuals.
• Classification accuracy for the 1.2 Gy (moderately exposed) group was challenging, with significant misclassifications.
• While generally effective, some assays exhibited systematic dose estimate shifts or extreme outliers, linked to sample material, team experience, or methodology.

Conclusions:

• The RENEB ILC demonstrated that most tested assays are applicable for identifying unexposed and highly exposed individuals and relevant medical groups.
• Challenges remain in accurately classifying moderately exposed individuals and addressing assay-specific outliers and systematic biases.
• Regular ILCs are essential for identifying research needs, optimizing assay performance, and improving future radiation dose reconstruction strategies.