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European Union Network of Laboratories for the Validation of Alternative Methods (EU-NETVAL)

EU-NETVAL is an EU Reference Laboratory for alternatives to animal testing (EURL ECVAM) network of specialised laboratories set up in response to Directive 2010/63/EU on the protection of animals used for scientific purposes. The Directive requests that EU Member States assist the European Commission in the validation of alternative methods. Currently there are a total of 33 members, selected against predefined Eligibility Criteria and endorsed by the Member State National Contact Points (NCP). 

EU-NETVAL's mission, defined in the Terms of Reference, is to provide support for EURL ECVAM validation studies to assess the reliability and relevance of alternative methods that have potential to replace, reduce or refine the use of animals for scientific purposes. EURL ECVAM coordinates EU-NETVAL and works closely with the European Commission's Directorate-General for Environment to facilitate interaction with the NCPs.  

The network holds a range of expertise and competences and includes laboratories experienced in advanced in vitro procedures, various test systems and measurement techniques, which are considered important to address specific aims and objectives identified in EURL ECVAM's strategies to achieve Three Rs impact in different areas of regulatory safety testing. 


Activities of EU-NETVAL

Validation of thyroid hormone disruption methods

Concern over the potential for environmental chemicals to perturb hormone systems has led to the development and implementation of a number of OECD Test Guidelines for the screening and testing of endocrine disrupting chemicals. Although a number of methodologies have been developed to interrogate reproductive steroids, incorporation of test methods to evaluate disruptors of thyroid hormone signalling pathways has been limited, owing largely to the complexity of the thyroid system.

EURL ECVAM identified a number of Thyroid Hormone Disruption (THD) in vitro methods with validation potential, based on the OECD scoping paper (OECD, 2014) and with input from meetings and workshops. This large set of methods was used as the starting point for the validation of 18 in vitro THD methods for the identification of modulators of thyroid hormone signalling.

An overview of all 18 THD in vitro methods, including the list of the EU-NETVAL participants and test method developers, can be found in the EURL ECVAM status report of 2022.

The validation was carried out in collaboration with 15 facilities from EURL ECVAM’s network of specialised laboratories, EU-NETVAL (Belgium, Czech Republic, Finland, Germany, Italy, Poland, Portugal, en, Spain, Sweden,The Netherlands).

Currently, the results of the validation study are being evaluated at OECD by a panel of experts. Standard Operating Procedures (SOPs) and study reports can be found at EURL ECVAM’s TSAR.

Validation of a Transactivation assay for detection of (anti)androgenic activity of chemicals

EURL ECVAM carried out a validation study of the in vitro method AR-CALUX. This method is a reporter-based assay where osteosarcoma cells, stably transfected with a human androgen receptor, express luminescence when presented with chemicals that have (anti)androgenic potential. The method was submitted by the Dutch company BioDetection Systems (BDS).  

From EURL ECVAM's network of specialised laboratories, EU-NETVAL, three facilities (France, Sweden and the UK) were selected to participate in this validation study as well as the test method developer.   

The validation study consisted of a transfer phase, within and between laboratory reproducibility assessment, and relevance assessment. After a peer review of the validation report by ESAC, the method was included in an OECD Test Guideline (TG).  After reviews  by the OECD Working Group of National Co-ordinators of the TGs programme, the TG was adopted in 2019. This TG458 on Androgen Receptor Transactivation Assays includes 3 mechanistically similar methods: the AR-CALUX method and two additional ARTAs (developed by Japan and Korea). 

Guidance Document on Good In Vitro Method Practices (GIVIMP)

The Organisation for Economic Cooperation and Development (OECD) published its Guidance on Good In Vitro Method Practices (GIVIMP) to ensure the reliability and integrity of in vitro data used for the safety assessment of chemicals. It targets all key players involved in the process and covers in vitro method development, standardisation, validation, harmonisation and international acceptance. The guidance document is intended to support method developers and end-users working in academic, industry or government laboratories across all 36 OECD member countries and beyond.  

The development of GIVIMP was coordinated by EURL ECVAM within the context of a project of the OECD Test Guidelines Programme.

A large number of international experts, including members of a dedicated OECD expert group and EU-NETVAL, contributed to the state-of-the-art knowledge gathered within the guidance document.  

Guidance Document on Good In Vitro Method Practices (GIVIMP)

EU-NETVAL surveys

A number of surveys have been conducted over the past years:   

  • Use and transferability of in vitro methods based on complex test systems or technologies
  • Complex test systems, complex test items and complex detection systems & techniques
  • Miniaturised Ames in vitro method(s)
  • Uptake of skin sensitisation in vitro methods
  • Facilitating knowledge sharing in the Three Rs through targeted training on alternative methods

EU-NETVAL meetings

EU-NETVAL holds regular meetings with all members. The main objectives of the meetings include providing the members with updates on the current state of the network as well as the opportunity to discuss progress in the validation of in vitro methods, training and dissemination activities, and other related developments. 

EU-NETVAL meeting 20-21 September 2023
EU-NETVAL meeting 20-21 September 2023


The highlights and summary records of past EU-NETVAL meetings are provided below.


EU-NETVAL meeting 2023

  • European Commission and EURL ECVAM updates  
  • Validation principles and practice
  • Transferability of in vitro methods ​
  • Perspectives from CRO and Industrial end-users: Panel discussion with invited panellist from Eurofins, ABICH, CRL, BASF followed by an open discussion
  • Thyroid related validation study:
    • Introduction to the study
    • flash presentations by the EU-NETVAL participants to the study
    • data related assessment
    • follow-up with OECD and PARC   
  • Reflections on future EU-NETVAL activities

EU-NETVAL MEETING 2023 Summary record (available soon). 


EU-NETVAL meeting 2019

  • Updates on AR-CALUX in vitro method
  • Updates on defined approaches and OECD Test Guidelines for the skin sensitisation in vitro methods
  • Updates on genotoxicity and the potential regulatory use of the OECD work regarding the non-test Guideline method miniaturised Ames assay
  • Updates on the EFSA and OECD collaborative efforts for assessing alternative methods to detect adverse effect induced by chemicals that affect the developing nervous system
  • Updates on the status of the large scale EU-NETVAL validation study for the detection of thyroid hormone disrupting chemicals following up the OECD scoping document on the topic
  • In knowledge exchange sessions EU-NETVAL test facilities and invited experts agreed on key issues and recommendations to be considered in aiding the translation of more sophisticated methods into the regulatory domain, with particular emphasis on:
    • complex test systems (e.g. 3-dimensional tissue models or human induced pluripotent stem cells)
    • complex test items (e.g. chemical mixtures, biomedical devices, nanomaterials)
    • complex measurement technologies (e.g. automated imaging and 'omics)
    • the importance of advancing and implementing Good In Vitro Method Practices (GIVIMP) during in-house validation of in vitro methods
EU-NETVAL MEETING 2019 Summary record
(599.81 KB - PDF)


EU-NETVAL meeting 2017

  • Updates on AR-CALUX in vitro method
  • EU-NETVAL Survey on uptake of OECD Test Guideline skin sensitisation in vitro methods
  • Share experiences and knowledge on specific in vitro methods for the detection of thyroid hormone disrupting chemicals.
  • Experts were invited to host sessions addressing in vitro method definition and the practical management of test items and test systems
  • Exchanging information on the process of in-house validation (GIVIMP)
  • Potential regulatory use of non-Test Guideline methods such as the miniaturised Ames assay
    2 FEBRUARY 2022
    EU-NETVAL Meeting 2017 - Summary Record
    (1.73 MB - PDF)


EU-NETVAL meeting 2016

  • Open issues relating to Good In Vitro Method Practice
  • New in vitro methods with validation potential
  • Open issues relating to GIVIMP in preparation for the formal OECD process
  • Knowledge sharing sessions on specific in vitro methods for the assessment of skin sensitisation potential
EU-NETVAL meeting 2016 - Summary records
(523.07 KB - PDF)


EU-NETVAL meeting 2015

  • Progress report on the AR-CALUX validation study
  • Breakout groups to focus on specific areas of GIVIMP
  • Sharing knowledge within EU-NETVAL through training: New methods and training needs and capacities
EU-NETVAL meeting 2015 - Summary records
(851.75 KB - PDF)


EU-NETVAL meeting 2014

  • Introduction to the network by EURL ECVAM, DG Environment, DG Enterprise and the OECD
  • Planning of the AR-CALUX validation study
  • Discussions on GIVIMP
EU-NETVAL meeting 2014 - Summary records
(161.46 KB - PDF)