Validation is a term used in a wide spectrum of disciplines and generally refers to the process of assessing whether an entity (i.e. a product, process, system) fulfils pre-defined performance targets and specifications. In the area of alternative approaches these pre-defined targets and specifications relate mainly to (1) the repeatability and reproducibility of results obtained with an alternative approach or method, allowing conclusions on the reliability of the assay and (2) the assay's relevance for measuring or predicting relevant biological effects.
When animals are needed to satisfy legislative requirements (i.e. regulatory testing), the same questions on safety and efficacy need to be answered time and again - such as toxicity of a new chemical substance or potency of a vaccine, before these are released on the market. Contrary to for example basic research, methods in the area of regulatory testing are used routinely and repeatedly.
A significant reduction in animal use can be achieved with mutual acceptance of test data across different countries and regions of the world avoiding otherwise unnecessary re-testing. In most cases, this is only possible when the methods that are used for producing such data are formally assessed to be scientifically valid and fit for purpose.
Before allowing a product on the market that is to be used by the public, or to be released in the environment, regulators need to decide on the safety or the potency of such a product. Therefore regulators need to trust the reliability and relevance of the data provided by the test method, because these data form the basis for the decision on the safety/potency of a product.
The confidence in these test methods used in a regulatory context is gained through a formal (scientific) validation demonstrating the reliability and relevance of a particular approach, method, process or assessment for a defined purpose (OECD, 2005).
A ‘validated alternative method’, is one that has successfully gone through a formal validation process which today is a pre-requisite in certain (but not all) areas of regulatory testing when wider acceptance of the test results derived using the method is required.
Directive 2010/63/EU established the European Union Reference Laboratory for alternatives to animal testing, EURL ECVAM , and describes as one of its key tasks the co-ordination of formal validation studies at EU level to facilitate rapid uptake of new methods and approaches to replace reliance on animal testing.