In vitro methods

A test performed in vitro (latin: "in the glass") means that it is done outside of a living organism and it usually involves isolated tissues, organs or cells.

You can use in vitro data to fully or partly fulfil information requirements that would otherwise need data to be generated with tests on living organisms (in vivo tests).

In vitro methods are divided to those that meet internationally agreed validation criteria and to those that do not. For your REACH registration, preferably use methods that are sufficiently well-developed according to internationally agreed test development criteria (e.g. the European Centre for the Validation of Alternative Methods (ECVAM) pre-validation criteria).

The changes to the REACH Annexes VII and VIII in 2016 make in vitro test methods the default for certain toxicological properties. In most cases, no new in vivo studies are necessary for registrations below 100 tonnes for the classification or risk assessment of your substance.

Even if you have used an in vitro method that has not been internationally validated, you still need to submit your study results in your registration dossier as part of gathering all available information. You may also use them in a weight of evidence approach or to support the grouping of your substances.


  • Present a clear and detailed description of the results, the test conditions and the interpretation of the results. This is important if the study is used as a key study or as part of a weight of evidence approach.
  • Communicate clearly the limitations of the method.
  • Use a (preferably) validated method. Make sure that the results are adequate for classification and labelling and/or risk assessment and that you provide adequate and reliable documentation.
  • Your in vitro method needs to deliver reliable information that is comparable to that from the standard test. If not, you may then need in vivo testing.