Testing of chemicals

OECD Test Guidelines Programme



The OECD Guidelines for the testing of chemicals are a collection of the most relevant internationally agreed testing methods used by governments, industry and independent laboratories to assess the safety of chemicals. They are primarily used in regulatory safety testing and subsequent chemical notification and registration. The set of Test Guidelines is updated on a regular basis to keep pace with progress in science and countries’ regulatory needs. OECD-wide networks of national coordinators and national experts provide input from scientists in government, academia, and industry. Learn more on OECD Test Guidelines Terminology.

What is the Mutual Acceptance of Data (MAD)?

The MAD system helps to avoid conflicting or duplicative national requirements, provides a common basis for co-operation among national authorities and avoids creating non-tariff barriers to trade. OECD countries and full adherents have agreed that a safety test carried out in accordance with the OECD Test Guidelines and Principles of Good Laboratory Practice in one OECD country must be accepted by other OECD countries for assessment purposes. This is the concept of “tested once, accepted for assessment everywhere*”. This saves the chemicals industry the expense of duplicate testing for products which are marketed in more than one country. 

* While the receiving government must accept the study, how it interprets study results is its own prerogative. 


Did you know?

By reducing duplication, and creating a framework for the sharing of work, the MAD system saves governments and industry around EUR 309 million each yearas well as reduces the number of animals used in such testing.

Source: Saving Costs in Chemicals Management, OECD (2019)


   Test Guidelines and Series on Testing and Assessment

  Overview of the Test Guidelines Programme

 Highlight on specific activities

GLP world icon Council Act and Test Guidelines adopted

Second call for data on the miniaturised Ames Test

A first call for data was organised in March 2018. A large number of laboratories participated in the call, yielding data covering several versions of the miniaturised Ames test. However, there has been clear differences between assays in the amount of data collected. In order to improve the coverage of the dataset, a complementary call for miniaturised bacterial reverse gene mutation test data is now organised.

This second call is open to any miniaturised bacterial reverse gene mutation tests, with a specific focus on assays for which gaps have been identified, i.e. the 24 well plate and Ames II. Data submitted should be provided in pairs, i.e. for each chemical submitted, data are needed both for a miniaturised Ames test and a corresponding standard Ames test, in order to have matched mini Ames - standard Ames data.

These data would serve as a basis for performing a retrospective validation study of the available versions of the miniaturised Ames test, which will be described in a Detailed Review Paper (DRP) under preparation.

This project is included in the Programme of Work of the Working Group of the National Coordinators of the Test Guidelines Programme and is led by three co-lead countries, Belgium, the Netherlands and the US.

The collected data will be used and analysed by the expert group on the miniaturised Ames test. In case of confidential data please specify it or code the chemicals in the submission.

Deadline for submission of data: Tuesday 10 December 2019.

Once the submission form is complete, please send the file back to

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