The Endotoxin Activity Assay (EAA) is a diagnostic tool used to measure the activity of endotoxins, specifically lipopolysaccharides (LPS), in whole blood.
This assay is used in critically ill patients to detect systemic endotoxemia, which is often associated with sepsis and septic shock.
A blood sample with an anti-endotoxin antibody and added LPS, assaying the oxidative burst of primed neutrophils, which is detected by chemiluminescence.
The results are expressed on a scale from 0 (absent) to 1 (maximal), and categorized as “low”.
The EAA test shows a high negative predictive value for ruling out Gram-negative infections and can stratify patients at risk of progressing to severe sepsis.
The amount of chemiluminescence is proportional to the concentration of LPS in the sample and is a measure of the endotoxin activity in the blood.
The assay reacts specifically with the Lipid A moiety of LPS of Gram-negative bacteria and does not cross-react with cell wall constituents of Gram-positive bacteria and other microorganisms.
It is a rapid and reliable bedside test that can help guide clinical decisions in the management of sepsis and septic shock.