Many people ask what goes into a test. There’s no quick answer for this, so we’re going to try and break some of it down here. Different manufacturers make different amounts of information available, but here’s a quick rundown of what you to look for.
Identifying an antibody
Every antibody used for gluten detection is different. Some detect oats; some overestimate rye; some underestimate barley; some mostly miss ancient wheats; some are specific to alpha-gliadin; and some are more broadly reactive to multiple gluten proteins. Antibodies are selected by kit manufacturers based on what is available or what is desired. This often involves screening large numbers (dozens or more) of potential antibodies and screening based on specificity and crossreactivity which is performed in more detail during assay validations. We use the Skerritt antibody because it is well-tested, has a broad reactivity to various gluten proteins, and can detect all strains of wheat, rye, and barley we have tested without any crossreactivity to oats or any ingredients we have tested. We are also able to make this antibody from a cells that give us the same antibody year after year. This allows us absolute control of quality and consistency. Differences between antibodies mean results may vary slightly — every antibody and kit has best applications, with no one being the absolute best in all situations.
Assay validations
All kits go through validations internally before a kit is complete. The detail in these validations can vary greatly. Our validations are based on the guidance at the time from the AOAC used to apply for our kit’s PTMSM status. This required ~100 unique samples, control materials made from different matrices with known gluten concentrations, and testing by multiple users. Additionally, any industry certification requires third-party validations by an independent laboratory. There are a handful of laboratories that have extensive experience running these sort of validations regularly.
What constitutes a third-party validation or an independent laboratory?
The scientific field has strict requirements on independence when it comes to research and publications. An independent lab is one without any financial or personal ties to the manufacturer. Any potential conflicts are disclosed up-front, regardless of whether any bias is present — it is up to the reader or community to determine the potential impact of any such conflicts. In most fields, it is likely the manufacturer and laboratory are complete strangers, but potential conflicts are based on having any formal relationship. This means the independent lab does not appear on the manufacturer’s manuscripts, did not participate in product development, and has no personal or financial stake in the product or company. Occasionally a junior member of a team may have worked with the other party, but this is something that would likely be disclosed if they participated in the work being performed. Improper or incomplete disclosures can permanently tarnish a researcher’s reputation and result in retraction of a manuscript for misconduct or ethical violations.
What does a validation mean to me?
Validations typically contain details that are formatted for an industry or scientific community. This can make it difficult to interpret for other users. The key is to identify the information that matters to you.
Do you want to know if your food can be tested on this assay? Look for it or a similar product in the validation.
Are you looking to see how accurate the assay is? Look for the data at or near the limit of detection.
Are you looking to see how variations in testing affect results? Look for a section of ruggedness.
Are you looking for assay variations? Look for a section comparing results of different users and/or different kit lots.
One key takeaway here is that there is a lot of information out there that you may not be aware of that can help you in your journey. Check with manufacturers, beware of conflicts, and know what you are testing and you’ll come away as a better informed and more confident consumer.
Our validations have been updated regularly for nearly 15 years.
Our third party validation for the AOAC Research Institute was performed by Q Laboratories and is available with our PTM certification here.
The 2025 version of our internal validation is available here.