How to Verify a Certificate of Analysis and Spot a Fake

A certificate of analysis is only useful if it is real and if it describes the material in your hands. Neither is guaranteed. Certificates can be copied from another batch, edited after the fact, or made from scratch on a generic template, and a polished PDF can look convincing either way.

The good news is that most fakes fail simple checks you can do yourself in a few minutes: matching numbers, confirming the report with the lab that supposedly issued it, and looking closely at the document for signs of reuse or editing. This guide walks through those checks in order and ends with what even a genuine certificate cannot tell you.

What a checkable certificate includes

Start by making sure the document has enough detail to check at all. Labs that work to ISO/IEC 17025, the international standard for testing laboratories, are expected to put certain items on every report. Labs outside that system usually include most of them too, because they are what make a report traceable.

• The lab's name and address, plus contact details you can find independently.
• A unique report number, often printed on every page, such as “Report 26-10482, page 1 of 3.”
• A sample description that names the product, the stated amount and the batch or lot number.
• Dates: when the sample was received, when it was tested and when the report was issued.
• The methods used, such as HPLC for purity and mass spectrometry for identity, with results and units.
• Who authorized the report, by name or role.

If several of these are missing, there is little you can verify, and that is a finding in itself.

Certificate of analysisExample only

Product	Example peptide, 10 mg vial
Batch / lot	EX-2611-04	1
Test date	14 Oct 2026
Method	HPLC (UV 214 nm), ESI-MS	2
Purity (HPLC)	99.2%	3
Identity (MS)	Observed mass matches expected	4
Content	10.3 mg per vial
Laboratory	Independent lab name and address	5
Verification	Report number you can check with the lab	6

Match the batch number to your vial

The batch or lot number is the thread that ties a certificate to physical material. Read the number on your vial label and compare it, character by character, with the one on the certificate. “EX-2611-04” and “EX-2611-40” are different batches.

A few other details should line up as well:

• The product name and stated amount match the label, for example a 10 mg vial on both.
• The test date falls before the vial shipped, and the issue date falls on or after the test date.
• The certificate was issued for that batch, not described as “representative” or “typical.”

If the vial has no batch number, or the supplier sends a certificate for a different batch and calls it equivalent, you cannot link the paperwork to your material. Ask for the certificate that matches your batch before going further.

Confirm the report with the lab

The strongest single check is asking the issuing lab whether the report is genuine. Find the lab's contact details yourself, from its own website or a public business listing, rather than using the phone number or email printed on the certificate. A forged document can list contact details that lead straight back to the forger.

Send the report number, the batch number, the product name and the issue date, and ask two questions: did you issue this report, and do the results on this copy match your records? Some labs offer an online lookup where you enter the report number or scan a QR code. If you use a QR code, check that it opens a page on the lab's real domain, not a lookalike address or a file-sharing link.

Practice varies. Some labs will confirm a report to anyone who has the number. Others discuss results only with the client who paid for the test, or confirm only that the report exists. A lab that declines to share details is not proof of a fake, but until something confirms the report, treat it as unverified.

Check the lab itself

Next, make sure the lab is a real, independent testing business. Look for a website with a physical address, a description of its testing services and a history that predates the certificate. Be wary if the lab's name appears only on supplier pages, or if it shares an address, owner or website design with the seller.

If the certificate claims accreditation, check that too. Accreditation bodies publish directories where you can search by lab name or certificate number. Confirm that the listing is active, that it names the same lab and site, and that its scope covers the kind of test on the report. Accreditation is granted method by method, so a lab can be accredited for some tests and not others.

Accreditation is not the only path to a sound result, and many capable labs work without it. But a claim of accreditation that does not check out is a serious problem.

Signs a certificate has been reused

Reuse is the most common problem: a real report for one batch presented as covering others. Watch for these patterns:

• The same report number on certificates for different batches, amounts or products.
• An identical chromatogram, down to the smallest peaks, across products that should look different.
• A stale date, such as a test from many months ago for a batch described as new.
• A different client name: the report names a company other than the seller. That can mean the certificate was taken from a manufacturer or another reseller and passed off as the seller's own.
• An identity result that doesn't fit, such as an expected mass that doesn't belong to the product named on the label.

Some resellers do buy batches that were tested upstream, and that can be legitimate if the seller says so and the batch numbers line up. The problem is a certificate presented as something it is not.

Signs of editing and generic templates

Edited certificates often show small seams. Look for fonts or sizes that change within one table, digits that look blurred or sit slightly off the line, white boxes behind numbers, or columns that no longer align. Check that the numbers agree with each other: if the peak table lists a main peak area of 97.4%, the summary should not say 99.5%. Results that are perfectly round, such as 100.00% purity, deserve a question.

A file's properties can show which program last saved it, but plenty of genuine reports are exported or re-saved with ordinary software. Treat that as a hint, never as proof.

Generic templates are a different problem: a document that looks like a certificate but contains nothing checkable. Common signs include a lab name such as “Quality Control Department” with no address, no report number, no method, no dates, no signatory and a single line reading “Purity: 99%+.” If the same layout appears word for word on unrelated sellers' sites, it most likely came from a template rather than a lab.

What a genuine certificate still can't tell you

Even a confirmed report has limits. It describes the sample the lab received, on the day it was tested. It cannot prove that your vial came from that sample, that the batch was filled evenly, or how the material was stored and shipped afterward. Testing labs typically state on the report that results apply only to the items tested.

A matching batch number, a lab that exists and a report the lab confirms together give you good reason for confidence. Where the result matters to your work, independent testing of a sample from your own batch is the only way to close the remaining gap.