Most buyers scan a certificate of analysis for the purity percentage and move on. The endotoxin result, usually reported in EU/mL from an LAL (Limulus Amebocyte Lysate) test, gets less attention, despite testing for something a purity percentage says nothing about.
What LAL Testing Actually Measures
The LAL test reacts to endotoxins — a component of certain bacteria’s outer membrane that remains active even after sterilization kills the bacteria. Sterility and endotoxin level are two different measurements answering two different questions.
“Sterile and endotoxin-free are two different claims. A lot of COAs only ever make the first one.”
— a sterile manufacturing quality consultant interviewed for this pieceWhy the Number Matters More for Injectables
Endotoxin exposure through injection bypasses barriers that make other exposure routes lower-risk, which is why pharmaceutical manufacturing sets explicit endotoxin limits for injectable products.
Reading the Result Against a Real Limit
A raw EU/mL number with no stated limit, or a COA that doesn’t run the test at all, tells a buyer nothing they can act on.