The cytokinesis-block micronucleus cytome assay is a comprehensive method for measuring DNA damage, cytostasis, and cytotoxicity. It specifically scores DNA damage events in once-divided binucleate (BN) cells, including micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs). The assay also measures cytostatic effects through the proportion of mono-, bi-, and multinucleated cells, and cytotoxicity via necrotic and apoptotic cell ratios. The procedure can take up to 5 days to complete. The CBMN assay has evolved to measure various chromosomal abnormalities and has applications in biomonitoring, genotoxicity testing, nutrigenomics, pharmacogenomics, and predicting radiation sensitivity and cancer risk. The assay is reliable and reproducible, making it a standard cytogenetic test for genetic toxicology. The CBMN assay is particularly useful for studying cellular and nuclear dysfunction caused by aging, micronutrient deficiency, genotoxin exposure, and genetic defects. It has been validated in human studies and is being used to predict disease outcomes, such as cancer risk. The assay provides a harmonized approach for studying genotoxicity and cytotoxicity in vitro and ex vivo, which is crucial for modeling and predicting in vivo effects in humans.The cytokinesis-block micronucleus cytome assay is a comprehensive method for measuring DNA damage, cytostasis, and cytotoxicity. It specifically scores DNA damage events in once-divided binucleate (BN) cells, including micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs). The assay also measures cytostatic effects through the proportion of mono-, bi-, and multinucleated cells, and cytotoxicity via necrotic and apoptotic cell ratios. The procedure can take up to 5 days to complete. The CBMN assay has evolved to measure various chromosomal abnormalities and has applications in biomonitoring, genotoxicity testing, nutrigenomics, pharmacogenomics, and predicting radiation sensitivity and cancer risk. The assay is reliable and reproducible, making it a standard cytogenetic test for genetic toxicology. The CBMN assay is particularly useful for studying cellular and nuclear dysfunction caused by aging, micronutrient deficiency, genotoxin exposure, and genetic defects. It has been validated in human studies and is being used to predict disease outcomes, such as cancer risk. The assay provides a harmonized approach for studying genotoxicity and cytotoxicity in vitro and ex vivo, which is crucial for modeling and predicting in vivo effects in humans.