What is Endotoxin Testing?

Endotoxin & Pyrogen Foundational 5 min

In short

Endotoxin testing detects bacterial endotoxins — fragments of the outer membrane of Gram-negative bacteria — in pharmaceutical products, medical devices and water. Because endotoxins can cause fever and severe reactions even in tiny amounts, regulators require every parenteral product to be tested and to fall below a defined endotoxin limit.

Endotoxins are lipopolysaccharides (LPS) released when Gram-negative bacteria break down. They are heat-stable and are not removed by ordinary sterilisation, so a product can be sterile yet still contain dangerous endotoxin.

Testing quantifies the endotoxin present and compares it to the product's endotoxin limit, which is derived from the maximum dose a patient may receive. The three established approaches are the LAL test, recombinant Factor C (rFC), and the Monocyte Activation Test (MAT).

Why it matters

Even nanogram amounts of endotoxin can trigger a pyrogenic response. Reliable detection protects patients and is a release requirement for every injectable product.

Frequently asked

Why is endotoxin testing required?

Endotoxins trigger a strong pyrogenic (fever) response and can cause septic shock, so pharmacopoeias require release testing of all parenteral products and many medical devices.

What is the endotoxin limit?

The endotoxin limit is the maximum amount of endotoxin allowed per dose, calculated from the threshold pyrogenic dose and the maximum human dose of the product.

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