Identity vs Identification in Peptide Testing
What is an identity test?
An identity test checks whether a sample matches a known reference standard for a specified product. The lab runs chromatographic analysis on the sample and compares the result against a reference for the product listed on the label. The outcome is binary: pass (the sample matches) or fail (it does not).
This is the test included in the standard Finnrick testing panel.
How does this work in practice?
Finnrick sends anonymized samples to the lab with the expected product name on the label. The lab has no information about the vendor or the buyer. It runs the analysis of the sample, compares the chromatographic profile of the sample against its reference library for that product, and reports whether the two match.
A pass means the sample is consistent with the reference standard. A fail means it is not: the sample contains something other than what was expected.
Why identity testing rather than full identification?
Identity testing answers the question most relevant to the Finnrick testing model: does the product match what the vendor says it is?
Full identification of an unknown compound — sometimes called blind testing or more formally de novo sequencing — is a different analytical process. It answers a different question: what is this substance? That analysis is not part of the standard testing panel.
The identity approach is designed around the way Finnrick testing works: large volumes of samples, tested against specific product claims, with results published for anyone buying from the same vendor.
Blind testing results would not produce data that is useful beyond that individual sample. That is why such testing isn't part of the Finnrick process.
What if my sample fails the identity test?
A fail result means the chromatographic profile did not match the reference standard. It does not tell you what the sample contains, only that it is not consistent with the expected product.
If you need complete identification of an unknown peptide, that requires a separate analytical process not currently available through Finnrick.