Endotoxin Units (EU), rather than units of weight, is a measure of the activity of endotoxin. It was developed by the FDA for comparison testing because the potency of endotoxin depends on a variety of factors: polysaccharide chain length, aggregation, solubility in biological fluids, bacterial source, associated substances, etc. Expressing endotoxin concentrations in EU addresses the issue of different potencies of different endotoxins.
Please use the following example to convert your endotoxin level: 10 EU/mL = 1.0 ng/mL