Laboratory Intercomparison of the Cytokinesis-Block Micronucleus Assay

• Published in: Radiation research 2013-08, Vol.180 (2), p.120-128
• Main Authors: Romm, H., Barnard, S., Boulay-Greene, H., De Amicis, A., De Sanctis, S., Franco, M., Herodin, F., Jones, A., Kulka, U., Lista, F., Martigne, P., Moquet, J., Oestreicher, U., Rothkamm, K., Thierens, H., Valente, M., Vandersickel, V., Vral, A., Braselmann, H., Meineke, V., Abend, M., Beinke, C.
• Format: Article
• Language: English
• Subjects: Adult; Automation; Biological Assay - methods; Calibration; Cells, Cultured - radiation effects; Cells, Cultured - ultrastructure; Cytokinesis - radiation effects; Dose-Response Relationship, Radiation; Dosimetry; Estimate reliability; Humans; Laboratory Proficiency Testing; Laboratory techniques; Leukocytes - radiation effects; Leukocytes - ultrastructure; Male; Manuals; Micronucleus tests; Micronucleus Tests - methods; NATO BIODOSIMETRY STUDY; Procedure manuals; Radiation dosage; Radiation Injuries - diagnosis; Radiation Injuries - genetics; Radioactive Hazard Release; Radiometry - methods; Reproducibility of Results; Sensitivity and Specificity; Single-Blind Method; Solar X rays; Space life sciences; Time Factors; Triage; Triage - methods
• ISSN: 0033-7587; 1938-5404
• DOI: 10.1667/RR3234.1

The focus of the study is an intercomparison of laboratories' dose-assessment performances using the cytokinesis-block micronucleus (CBMN) assay as a diagnostic triage tool for individual radiation dose assessment. Homogenously X-irradiated (240 kVp, 1 Gy/min) blood samples for establishing calibration data (0.25–5 Gy) as well as blind samples (0.1–6.4 Gy) were sent to the participants. The CBMN assay was performed according to protocols individually established and varying among participating laboratories. The time taken to report dose estimates was documented for each laboratory. Additional information concerning laboratory organization/characteristics as well as assay performance was collected. The mean absolute difference (MAD) was calculated and radiation doses were merged into four triage categories reflecting clinical aspects to calculate accuracy, sensitivity and specificity. The earliest report time was 4 days after sample arrival. The CBMN dose estimates were reported with high accuracy (MAD values of 0.20–0.50 Gy at doses below 6.4 Gy for both manual and automated scoring procedures), but showed a limitation of the assay at the dose point of 6.4 Gy, which resulted in a clear dose underestimation in all cases. The MAD values (without 6.4 Gy) differed significantly (P = 0.03) between manual (0.25 Gy, SEM = 0.06, n = 4) or automated scoring procedures (0.37 Gy, SEM = 0.08, n = 5), but lowest MAD were equal (0.2 Gy) for both scoring procedures. Likewise, both scoring procedures led to the same allocation of dose estimates to triage categories of clinical significance (about 83% accuracy and up to 100% specificity).