RENEB Inter-Laboratory Comparison 2021: The Cytokinesis-Block Micronucleus Assay

Vral, Anne; Endesfelder, David; Balázs, J; Beinke, Christina; Petrenci, C Cuceu; Finot, F; Garty, Guy; Hadjiiska, Ljubomira; Hristova, Rositsa; Ivanova, Ilonka; Lee, Y; Lumniczky, K; Milanová, Marcela; O, Gil; Oestreicher, Ursula; Pajić, Jelena; Patrono, Clarice; Pham, Ngoc-Duy; Perletti, Gianpaolo; Seong, Ki Moon; Sommer, Sylwester; Szatmári, T; Testa, Antonella; Tichý, Aleš; Tran, Thong; Wilkins, Ruth; Port, Matthias; Abend, Michael; Baeyens, Ans

doi:10.1667/rade-22-00201.1

Cited by 7 publications

(6 citation statements)

References 38 publications

(54 reference statements)

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“…Unexpectedly, the point estimates of the doses and their corresponding 95% confidence intervals were systematically higher than the reference doses. The latter could only be revealed due to the high number of participating laboratories and was, interestingly, also observed for other cytogenetic methods (29,42,43). This systematic bias might be introduced due to differences regarding the irradiation or experimental setup between the calibration curves used by the participants and the test samples, by problems during the transport of the samples or by problems with the irradiation setup.…”

Section: Discussionmentioning

confidence: 89%

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

et al. 2023

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After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0–1 Gy), moderately (1–2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semi-automatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

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Section: Discussionmentioning

confidence: 89%

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

et al. 2023

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“…Using a conversion factor between enamel/air kerma of 6.5 (28), the results agreed well with the air kerma references. Moreover, for cytogenetic assays (DCA, CBMN, FISH and PCC) the dose estimates were systematically higher than the reference doses (26)(27)(28)(29). This systematic shift can partly be attributed to differences in the biological effectiveness between the irradiation sources used for the establishment of calibration curves (mostly 60 Co or 137 Cs gamma rays) and for the exposure of the samples of this ILC (X rays, 240 kVp).…”

Section: Ilc 2021mentioning

confidence: 87%

“…In total 46 organizations from 27 countries participated in the RENEB ILC 2021. Several assays for biological dosimetry (DCA, CBMN, FISH, GE, yH2AX, PCC) and physical retrospective dosimetry (EPR, OSL, TL) were applied (Table 2) and the results for most of the assays are published in a number of papers in this special issue (26)(27)(28)(29)(30)(31). Blood was irradiated in terms of dose in water and various different materials (electronic components and glass from mobile phones, watch glass and mini-biopsies of tooth enamel) were irradiated in terms of air kerma with 0, 1.2 and 3.5 Gy X-ray doses (240 kVp, 1 Gy/min, ;75 keV, 13 mA, HVL ¼ 0.63) at the Bundeswehr Institute of Radiobiology, Munich, Germany and sent to the participating laboratories.…”

Section: Ilc 2021mentioning

confidence: 99%

“…For yH2AX, the highest dose point was underestimated, due to saturation of the foci signal (yH2AX). In the assay specific papers (26,27,29,30,31) of this special issue and the inter-assay comparison paper (28) these observations are discussed in detail. In most cases it was possible to identify methodological problems which can help the participants with problematic results to improve their workflow in future.…”

Section: Ilc 2021mentioning

confidence: 99%

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What We Have Learned from RENEB Inter-Laboratory Comparisons Since 2012 With Focus on ILC 2021

et al. 2023

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Inter-laboratory exercises are important tools within the European network for biological dosimetry and physical retrospective dosimetry (RENEB) to validate and improve the performance of member laboratories and to ensure an operational network with high quality standards for dose estimations in case of a large-scale radiological or nuclear event. In addition to the RENEB inter-laboratory comparison 2021, several inter-laboratory comparisons have been performed in the frame of RENEB for a number of assays in recent years. This publication gives an overview of RENEB inter-laboratory comparisons for biological dosimetry assays in the past and a final summary of the challenges and lessons learnt from the RENEB inter-laboratory comparison 2021. In addition, the dose estimates of all RENEB inter-laboratory comparisons since 2013 that have been conducted for the dicentric chromosome assay, the most established and applied assay, are compared and discussed.

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“…For triage, this is less of an issue for high doses but can affect the lower limit of detection or falsely identify unexposed individuals as exposed. The recent RENEB (Running the European Network of Biological and retrospective physical Dosimetry) exercise showed that semiautomated scoring, where only the Mni-positive BNCs were confirmed, performs better in a blinded interlaboratory comparison [Vral et al, 2023]. CU used a slightly modified semi-automated scoring, with all BNCs automatically identified and imaged and the Mni manually scored in the captured digitized BNC images.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Isolated Lymphocyte and Whole Blood-Based CBMN Assays for Radiation Triage

Bertucci¹,

Wilkins²,

Lachapelle³

et al. 2023

Cytogenet Genome Res

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Following a mass-casualty nuclear/radiological event, there will be an important need for rapid and accurate estimation of absorbed dose for biological triage. The cytokinesis-block micronucleus (CBMN) assay is an established and validated cytogenetic biomarker used to assess DNA damage in irradiated peripheral blood lymphocytes. Here, we describe an intercomparison experiment between two biodosimetry laboratories, located at Columbia University (CU) and Health Canada (HC) that performed different variants of the human blood CBMN assay to reconstruct dose in human blood, with CU performing the assay on isolated lymphocytes and using semi-automated scoring whereas HC used the more conventional whole blood assay. Although the micronucleus yields varied significantly between the two assays, the predicted doses closely matched up to 4 Gy – the range from which the HC calibration curve was previously established. These results highlight the importance of a robust calibration curve(s) across a wide age range that match the exposure scenario as closely as possible and that will account for differences in methodology between laboratories. We have seen that at low doses, variability in the results may be attributed to variation in the processing whilst at higher doses the variation is dominated by inter-individual variation in cell proliferation. This inter-laboratory collaboration further highlights the usefulness of the CBMN endpoint to accurately reconstruct absorbed dose in human blood after ionizing radiation exposure.

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RENEB Inter-Laboratory Comparison 2021: The Cytokinesis-Block Micronucleus Assay

Cited by 7 publications

References 38 publications

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

What We Have Learned from RENEB Inter-Laboratory Comparisons Since 2012 With Focus on ILC 2021

Comparison of Isolated Lymphocyte and Whole Blood-Based CBMN Assays for Radiation Triage

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