# Commission Regulation (EU) No 544/2011 of 10 June 2011 implementing Regulation (EC) No 1107/2009 of the European Parliament and of the Council as regards the data requirements for active substances (Text with EEA relevance) (repealed), Division: Circumstances in which required

Extent: E+W+S+N.I.

If all the results of the in vitro studies are negative further testing must be done with consideration of other relevant information available (including toxicokinetic, toxicodynamic and physico-chemical data and data on analogous substances). 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 are positive, an in vivo test to investigate unscheduled DNA synthesis or a mouse spot test must be conducted.

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Source: https://www.legislation.gov.uk/eur/2011/544/annex/part/A/division/5/division/5.4/division/5.4.2/division/1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2011-544/annex/part-A/division-5/division-5.4/division-5.4.2/division-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.