Frequently Asked Questions

What test do I need for my material?

The place to start is to establish if you need the test results as part of a regulatory submission, or whether you want to discover a substance’s properties as part of a product development or pre-clinical programme. We’re always happy to advise before you start so please feel free to call if you’re unsure.

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.

Is XCellR8 GLP accredited?

Yes we are. Our Good Laboratory Practice (GLP) accreditation by the UK’s MHRA (Medicines and Healthcare Products Regulatory Agency) means that we can provide you with in vitro safety test data that can be used for compliance with a wide range of European and global regulations.

Where should I send my sample?

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

Where do you get your human cell cultures from?

We have long standing relationships with global biotechnology companies who we buy our tissue models from. They source them from consenting donors, usually as a by-product of cosmetic surgery.

What do you need from me to start a test?

Firstly, we ask you to approve our quote and send us a PO number. We’ll then ask you to fill in an information sheet about your product or ingredient which includes some information such as the lot number, expiry date, purity and storage conditions required. We’ll ask for a description of the item (its name, colour and physical state) which will need to match the sample you supply. For some tests, we’ll also ask you to supply the molecular weight. If you have a Material Safety Data Sheet (MSDS), please also send us that. And last but definitely not least, we’ll need a sample of the item(s) you want to test sent to our laboratory in Cheshire, UK. 10ml if it’s a liquid or 10g if it’s a solid.

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.

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!)

How much of my product or material will you need to start a study?

10 ml if it’s a liquid or 10g if it’s a solid. This makes sure we’ve got enough of the item if you order more than one test. Please ensure your samples are clearly labelled, and match any documentation you send with them. If you don’t have this amount of your test item available, please call us to discuss your options.

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.

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.

Can you perform an Ames test at your laboratory?

We don’t provide the Ames test, as it uses animal components. We do provide the BlueScreen assay, a genotoxicity test that covers all types of genotoxicity: anugens, clastogens, and mutagens.

We don’t use a Purchase Order system or else Purchase Orders take a long time to issue in my organisation. Can I still start my study?

Yes. In these circumstances, we will usually issue the invoice at the beginning of the study and ask for payment within 30 days.

What units is antioxidant activity measured in for this assay?

XCellR8’s antioxidant test uses the OxiSelect™ method. The test is based on the intracellular conversion of DCFH to its fluorescentmetabolite (DCF). The reaction is inhibited by anti-oxidants, reducing the amount of fluorescence observed and so the test measures fluorescent intensity. You can read more information about OxiSelect™ here.

When will I receive my final report?

Most of our tests take 6-8 weeks from receipt of your sample to the first draft report, although please note sometimes it can be slightly shorter or longer depending on the test. We ask for your comments on the draft report within a week, and your final report will be with you after we’ve then completed our final QA checks.

Why do I need to provide an expiry date or a retest date for my sample?

We ask for an expiry or retest date to ensure that your test item is within its established shelf life specifications when stored under defined conditions – it’s all part of our work being performed in line with GLP (Good Laboratory Practice). It’s important that this is a true expiry date or retest date as it helps us make sure your test item is behaving as it should, and the results you get from us are correct.

Why do you need to know the purity of my test item?

Noting the purity of the item being tested is part of our GLP (Good Laboratory Practice) compliance. For certain tests, it allows us to ensure the correct concentration is being tested. It’s also another piece of key information that we check to make sure we have the right test item, and you get the right result.

What happens if I can’t provide a molecular weight for my test item?

This request only applies to the DPRA test. If you aren’t able to provide the molecular weight, you can detail the list of constituents with percentage compositions and we can approximate it using the guidance in the Test Guideline. As a last resort, the test item may be run neat (liquids) or dissolved at the highest soluble concentration (solids) then combined at a 1:10 or 1:50 ratio using the Cysteine and Lysine containing peptides respectively.

Do you offer work placements or internships?

We don’t have an internship programme at the moment but do offer occasional work placements to university students who are interested in animal-free test methods. If you would like to apply, please send your CV and a covering email explaining what our values mean to you to info@x-cellr8.com.

Can we interview someone from XCellR8 for a project we are working on?

Please send any media or study requests to info@x-cellr8.com for the attention of our Marketing Director, Susie Lee-Kilgariff.