Reference COAs vs. Batch-Matched COAs

Two Kinds of Report

A certificate of analysis covers the sample the laboratory tested and the batch it came from. Nothing else. Both kinds of report can be genuine; the difference is what they cover.

• Batch-matched. The product, labelled size and lot number on the report match the vials you'll receive.
• Reference. A report for the same compound but a different batch, a different labelled size, a partner's or another client's lot, or one with no batch number printed.

Where Reference Reports Come From

Reference reports are common, and most have an ordinary explanation. Knowing where one came from tells you what to ask for next.

• A shared batch. A batch made for, or shared with, another company, so the report names them as the client and carries their lot number.
• A different size. A report for one labelled size of a compound, published on a page that sells another size.
• A past lot. A report for a lot that has sold out, kept on the page after new stock arrived.
• No batch number. A report that names the compound but prints no lot, so it can't be matched to any vial.
• A sample report. A report sent with a first inquiry to show a supplier's testing, not tied to the order being quoted.

How to Tell Them Apart

• Find the lot or batch number on the report. No number means the report can't be matched to any vial.
• Compare it with the lot on the quote, then with the lot printed on the vials when they arrive. All three should be the same.
• Check the labelled size. A report for one size doesn't cover another, even of the same compound.
• Check the sample description and client field, if the report has one. A report issued to a different company is usually for a different lot.
• Verify it with the issuing laboratory. How to verify a peptide COA with the laboratory shows how.

A Worked Example

Here is a hypothetical case; the lot numbers are invented for illustration and don't belong to any real report. A buyer asks for 10 mg vials of a peptide. The supplier's product page shows a report for lot A-100 in the 5 mg size, issued to another company. The quote names lot B-200, 10 mg. When the vials arrive, they are printed B-200.

The report on the product page is a reference report on three counts: a different lot, a different size and a different client. It shows the compound has been tested before, but it says nothing certain about the vials in the box. The document that covers the order is the report for lot B-200 in the 10 mg size, and that is the one to ask for, check and keep with the order record.

Why It Matters

Each synthesis run is its own batch, with its own result. A clean report for last year's lot, or for a different size, says nothing certain about the units in front of you. A reference report still has value: it shows the supplier has had the compound tested by a named laboratory. It just isn't evidence for your lot.

If you resell or white-label, the report you publish for a product should be the one for the lot you're selling. Publishing a reference report as if it covered current stock is a documentation problem for you, not only for the supplier.

If You Publish Reports on Your Own Site

Buyers of your products will read your reports the same way you read your supplier's. Make it easy for them to match a vial to a document:

• Publish the report for the lot you're selling, with the lot number visible on the product page.
• Label any reference report as a reference, and say why: a different size, a past lot or another client.
• Keep past reports available after a lot sells out, for buyers still holding units from it.
• Update the page when the lot changes, so the report shown matches the stock being shipped.

What a Batch-Matched Report Still Doesn't Tell You

A batch-matched report is the right document, but it has limits. It covers the sample the laboratory tested from that lot, using the methods printed on it, and nothing beyond them. A report that gives purity and identity doesn't establish net content unless that test was run. It also can't show what happened to the units after the sample was taken, which is why receiving checks still matter.

Treat it as one link in a chain: the lot on the report, the lot on the quote and the lot on the vials should all agree, and the report should verify with the laboratory that issued it.

Questions to Ask Your Supplier

• Which lot will I receive, in which size?
• Is the report you've sent for that lot and size, or a reference?
• If it's a reference, why: a shared batch, a different size, a past lot or no batch number?
• Can I see the report for my lot before I pay?
• How can I verify the report with the laboratory that issued it?

How Our Site Labels Reports

Every report on our product pages and in the COA library carries one of two labels:

• Matches product and size: the product and labelled size printed on the report match the listing.
• Reference: the report is published but doesn't match the size or lot we list, and says why: a partner's lot, a different labelled size, or no batch number.

Neither Label Confirms Your Batch

Neither label on its own confirms that the batch on a report is the batch in current wholesale stock. That is confirmed on your quote: every wholesale lot comes with a certificate of analysis, and the quote names the lot you'll receive and its report. When the order arrives, check that the lot on the vials matches.

To get a quote with the lot and report named, build your list in the catalog. For what each line of a report means, see how to read a peptide COA, and for keeping reports organised across a catalog, see planning a product catalog and COA library.