Last updated · Published by Vesicae

How do you verify a COA (lab report)?

A lab report (COA) only proves something about your vial if the lot ID on the vial matches the report, the report lives on the independent lab's own site, and the lab is accredited for that test, so check all three yourself.

New to lab reports? Start with how to read a COA, then how to spot a fake COA. This method works for any supplier and takes a few minutes. It checks paperwork and traceability only.

Why isn't a COA alone proof?

A COA describes the sample the lab received. Without a lot ID that matches your vial, and a copy on the lab's own site, it could describe a different sample or have been edited.

Step 1: Read the lot ID on the vial label

Find the lot or batch ID printed on the vial itself, not on the website or the invoice. No lot ID on the vial means there is nothing to match a report against.

Step 2: Find the lab yourself and open its own record

Look up the testing lab's website independently (not through a link the seller gives you) and open the report on the lab's own domain, using the report or task number printed on the COA.

Step 3: Match 5 fields

Compare the lab name, report or sample ID, lot or batch ID, test date and client name between the COA and the lab's record. All five should match.

Step 4: Check the lab's accreditation scope

If the lab claims ISO/IEC 17025 accreditation, find it in the accreditation body's directory (such as A2LA or ANAB) and confirm the test method on your report is inside the lab's scope.

Step 5: Check the chain of custody

Ask whether the lot was named before testing, whether the sample was sealed, and who shipped it to the lab. A clear, dated record of who handled the sample is a good sign.

What are the red flags?

  • No lot or batch ID on the vial
  • The report is only available as a seller-hosted PDF or image
  • The report ID can't be found on the lab's own site
  • The lot ID, date or client on the report differ from the lab's record
  • The same report is used for several different lots
  • The lab can't be found, or its accreditation scope doesn't cover the method

Does "third-party tested" mean my vial was tested?

Not by itself. It means some sample was tested by someone. Only a lot ID match between your vial and the lab's own record ties that result to your vial.

Can a seller host a lab result?

A seller can post a PDF, but a PDF can be edited or reused. The stronger proof is the same report viewable on the lab's own site.

What can a QR code prove?

A QR code is a pointer, not proof. It is only useful if it opens a record that links to the lab's own report for the same lot ID.

What if something doesn't match?

Don't rely on the report. Contact the supplier with the lot ID and the mismatch, and consider an independent retest of a sealed sample at a second lab.

How does Named Lot handle this?

Named Lot records follow 7 checks, from naming the lot before testing to keeping failed lots visible. Read the Named Lot Standard, or verify a code on Named Lot.