The methodology for the examination of chromosomal aberrations in the context of REACH dossier evaluation was amended by the ECHA Member State Committee (MSC) following its June meeting.
These changes in the guidance to registrants are effective from 1 September 2022.
The main changes are as follows: - In order to meet the requirements of Annex VIII 8.4.2 of REACH, the default test is an in vitro micronucleus study (OECD Guideline 487) as it allows the identification of the mode of action (clastogenicity and/or aneugenicity). - In the case of in vitro identification of a risk of chromosomal aberration, it will most often be necessary to combine an in vivo comet assay (OECD Guideline 489) with an in vivo micronucleus test (OECD Guideline 474).
This method of combining tests reduces the number of tests and the number of animals tested.