Mass casualty scenarios of radiation exposure require high throughput biological dosimetry techniques for population triage, in order to rapidly identify individuals, who require clinical treatment. Accurate dose estimates can be made by biological dosimetry, to predict the acute radiation syndrome (ARS) within days after a radiation accident or a malicious act involving radiation. Timely information on dose is important for the medical management of acutely irradiated persons . The aim of the study was to evaluate the usefulness of the micronuclei (MNi) scoring procedure in an experimental mode, where 500 binucleated cells were analyzed in different exposure dose ranges. Whole-body exposure was simulated in an in vitro experiment by irradiating whole blood collected from one healthy donor with 60 MeV protons and 250 keV X-rays, in the dose range of 0.3-4.0 Gy. For achieving meaningful results, sample scoring was performed by three independent persons, who followed guidelines described in detail by Fenech et al. [2, 3]. Compared results revealed no significant differences between scorers, which has important meaning in reducing the analysis time. Moreover, presented data based on 500 cells distribution, show that there are significant differences between MNi yields after 1.0 Gy exposure of blood for both protons and X-rays, implicating this experimental mode as appropriate for the distinction between high and low dose-exposed individuals, which allows early classification of exposed victims into clinically relevant subgroups.