Cross-species genetic toxicity assessment accomplished by flow cytometric analysis of blood.

The formation of micronuclei in blood cells has been an established indicator of genotoxicity for decades. Standard microscopy methods are time-consuming and lack the objectivity that fully automated methods can provide. The ability of flow cytometric technology to rapidly and objectively survey thousands of cells for micronuclei can significantly improve the value of this endpoint. In addition, since many more cells can be scored, and specific populations can be targeted, species that historically have been difficult to obtain micronucleus data from, such as humans, can now be readily evaluated using this methodology. This unit describes a procedure for fixation, staining, and analysis of blood samples using materials supplied in MicroFlow kits (Litron Laboratories) and a single-laser flow cytometer. This methodology provides a reliable, robust assessment of chromosome damage that is used in basic science research as well as drug-safety screening programs at large pharmaceutical and chemical companies.