A sequential approach to testing with the rodent bone marrow micronucleus assay--obviation of the need for statistical analyses of data.

The 'sequential' protocol we use for the conduct of mouse bone marrow micronucleus assays is described. The most important criterion for activity in the assay is the reproducibility of any induced effects. The frequencies of micronucleated polychromatic erythrocytes among 239 male CBA control mice are displayed and discussed. Our decision to avoid statistical analysis when assessing mouse bone marrow micronucleus data is explained.