Micronucleus test

A micronucleus test is a test used in toxicological screening for potential genotoxic compounds. In vitro culture cells are checked for induced micronucleus formation.

A micronucleus is the erratic (third) nucleus that is formed during the anaphase of mitosis.

Using fluorescent in situ hybridization (FISH) with probes targeted to the centromere region, it can be determined if a whole chromosome, or only a fragment is lost.