Division Circumstances in which required

If all the results of the in vitro studies are negative further testing must be done with consideration of other relevant information available. The test can be an in vivo study or an in vitro study using a different metabolising system from that/those previously used.

If the in vitro cytogenetic test is positive, an in vivo test using somatic cells (metaphase analysis in rodent bone marrow or micronucleus test in rodents) must be conducted.

If either of the in vitro gene mutation tests is positive, an in vivo test to investigate unscheduled DNA synthesis or a mouse spot test must be conducted.