Resources

Browse our articles

Safety Testing

Browse all articles

Animal-free Testing

Browse all articles

Efficacy Testing

Browse all articles

Regulation and Compliance

Browse all articles

XCellR8 News

Browse all articles

Frequently Asked Questions

What is an assay?

Broadly speaking, assay is a scientific term that means test. It is often used by the pharmaceutical industry to describe the experimental procedure that quantitatively or qualitatively measures the presence, amount, or functional activity of a target entity (to get all Wikipedia about it!)

Does XCellR8 offer human patch testing?

No, we don’t but many clients use our in vitro tests as an early screen in product development before they get to more expensive human trials. They can also be used to generate supporting information in a weight-of-evidence approach to safety assessment. XCellR8’s tests may give you a binary classification on the effect of an ingredient, for example, Irritant or Non Irritant, or a more detailed classification to help you rank irritation potential. Please get in touch if you’d like to find out more.

Which skin sensitisation test do I need?

Current regulatory guidance for in vitro skin sensitisation testing is to adopt the “2 out of 3” approach, whereby 2 positive results out of the 3 tests (OECD TGs 442c, 442d and 442e) results in classification as a Skin Sensitiser. If you perform two of the tests and get matching results, this strategy states you can have confidence in the result without the third test. If they have different results, proceed to the third method to find a definitive result. Each of the three methods has different requirements regarding the solubility of your test item, so contact us to find out which will be best for you. You can also read more about the test methods here.

Where should I send my sample?

Please send all samples to XCellR8 (labs) Techspace One, Keckwick Lane, Daresbury, Cheshire, WA4 4AB, UK

How long will my test take?

XCellR8’s tests can take as little as 4 weeks, up to a maximum of 12 weeks. We’ll always try our best to accommodate urgent requests. Please do bear in mind that the timeframe starts at the point we receive your sample and the accompanying information that we ask for in order to start a study, and finishes when we send your draft report.

Which skin irritation test do I need?

This depends on whether you need the test for EU regulatory purposes, in which case Skin Irritation OECD TG 439 might be right for you, providing a binary answer as to whether your item is an Irritant or Non Irritant, or for product development. Our non regulatory test uses the ET50 method and is used to place your item into a rank order of irritation potential or compare it against industry benchmarks. We’re more than happy to chat through the different test methods, or can introduce you to one of our regulatory consultancy partners who can help you make the decision.