A Certificate of Analysis is the one page that tells you what is actually in the vial you received, as opposed to what the catalog says is in the product. It is issued per lot, it reports measured results against the product's specifications, and it is the document an auditor, a reviewer or a colleague repeating your work will ask to see.
What it's for
A product page describes a specification: what every lot has to meet. A CoA reports a lot: what this batch measured on the day it was released. The difference matters because biological reagents vary. Two lots of complement can both pass a minimum hemolytic titer and still differ in titer. Two lots of serum can both be non-hemolyzed and differ in protein. The CoA is how you find out which one you have, set your working dilution, and record the value alongside your data. In regulated manufacturing the same document is the formal release record. The ICH Q7 guidance on good manufacturing practice, adopted by the FDA, describes the certificate of analysis as the record that reports each lot's test results against its specifications (FDA).
What's on it
Identification first: product name, catalog number, lot number, and the date of manufacture or release. Match all three to the label on the vial.
Then the specifications and results, side by side. Each test the product is released on, the acceptance limit, and the value this lot measured. For our complement products that means the hemolytic titer. For sera and plasmas it is appearance and hemolysis grade. For sterile products, the sterility result. For products with an endotoxin specification, the LAL result per milliliter or per milligram.
The storage condition and expiry: the temperature the lot should be kept at, and the date through which the results are supported. And a sign-off, who released it and when.
A CoA doesn't usually restate general product information, safety data or handling instructions. Those live on the datasheet and the Safety Data Sheet.
Reading it
Look at the results, not the pass/fail column. A titer near the low end of the specification behaves differently from one near the top, and a hemolysis grade of "trace" is fine for some assays and a problem for others. Write the lot number and the relevant result in your notebook or LIMS with the experiment. When a result changes between lots, comparing the two CoAs is the first diagnostic. Note the expiry, and remember it assumes the stated storage condition. A lot that sat at 4 °C for a week is no longer the lot the certificate describes.
Finding yours
We publish lot certificates on this site. Search by lot number, product code or product name on the Certificates of Analysis page. Each product page also lists the certificates issued for that product, so you can look up a lot before it arrives or check one from years ago. If a lot number doesn't appear, or you need a certificate in a particular format for a regulatory filing, contact us with the product code and lot number and we'll send it.