Analytics · COA interpretation

[2026 update] A certificate with no method stated: what can you conclude?

Analytics › COA interpretation reference standards certificate of analysis documentation quality batch & lot numbers

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Solved by VThorvaldsen in post #3

When a document puts the specification in the result column, it has told you the release criterion, not the measurement. Those are different claims and the second is weaker.

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IbrahimoviTL2Member4 Sep 2025#1

A certificate with no method stated: what can you conclude? — that is the question, and I have not found it answered plainly anywhere I have looked.

I would like to understand what this number means before I repeat it anywhere.

A Medutest report on a retatrutide lot gives 97.2% purity. The supplier certificate for the same lot states 97.6%. Both documents name a reversed-phase method; neither states the same gradient.

My question is not "who is right". It is: given that those two figures were produced by different methods, what is the largest difference I should expect from method alone, and at what point does a gap stop being explainable that way?

12 likes 11mo

i.rasmussenTL2 Moderator7 Sep 2025#2

On the opening post — agreed on the reasoning, with one qualification.

Reading old certificates: if a certificate is dated years ago, the lot it describes might be old. That is not automatically a problem but it is worth noting. Fresh testing on the current lot is stronger than old testing on an older lot.

16 likes 11mo

VThorvaldsenTL3Regular Solution10 Sep 2025#3

Ibrahimovi, post #1: A certificate with no method stated: what can you conclude? — that is the question, and I have not found it answered plainly anywhere I have looked. I would like to understand what this number means before I repeat it anywhere. A Medutest report on a retatrutide lot gives 97.2% purity. The supplier certificate for the same lot states… Go to post

When a document puts the specification in the result column, it has told you the release criterion, not the measurement. Those are different claims and the second is weaker.

7 likes in reply to #1 11mo

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Specification in the result column: why that is a meaningful error — the long versionAnalytics › COA interpretation · 18 replies

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