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ForumsCOA & Analytical TestingPaid for independent testing and results did not match vendor COA Page 7

Paid for independent testing and results did not match vendor COA

PurityPaulOR Sat, May 9, 2026 at 3:54 AM 36 replies 1,050 viewsPage 7 of 8
B12Beth
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May 25, 2026 at 6:19 PM#31
josh_phd_bmore said:
Keep the original post as written when you update it, and add the correction underneath.

Right, and the exception is worth naming rather than left implied, because the exception is where people get into trouble.

34 7GraceAZ_72, carl_compliance, DanielChem_CHI and 31 others
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LeilaHI
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May 26, 2026 at 6:16 PM#32
josh_phd_bmore said:
Keep the original post as written when you update it, and add the correction underneath.

This is exactly what I could not find anywhere else. I will report back once I have actually tried it.

Last edited: May 26, 2026 at 11:16 PM
35 8VendorMark, COA_Karl, MikeFit_NJ and 32 others
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Dr.GastroMayo
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May 27, 2026 at 6:12 PM#33

From the other side of the consultation, briefly. The distinction that resolves most of these threads is between what is true on average and what is true for one person. Both are real; they answer different questions and get quoted as if they were the same one.

Last edited: May 27, 2026 at 11:12 PM
36 9COA_Karl, MikeFit_NJ, InsuranceTom and 33 others
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mark_tokyo
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May 28, 2026 at 6:07 PM#34
Dr.GastroMayo said:
The distinction that resolves most of these threads is between what is true on average and what is true for one person.

Adding a me-too, because a thread of one person's experience is not much use.

Last edited: May 28, 2026 at 9:07 PM
37 10HPLC_Greg, LibrarianMeg, bri_stats and 34 others
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A1cHero_PHX
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May 29, 2026 at 6:02 PM#35
Dr.GastroMayo said:
The distinction that resolves most of these threads is between what is true on average and what is true for one person.

There is a second half to this that has not been said yet. Inter-laboratory variation comes from real methodological differences, not sloppiness: which reference standard was used and how it was itself calibrated, the gradient and column, the detection wavelength, and where the integration baseline was drawn. A percentage point or two between competent labs is expected. What is not expected is a large gap, and the usual explanation there is that one report is not of the batch in your hand.

38 11jason_sac26, chris_chi24, tampaLisa73 and 35 others
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