The EndoCAb® IgA ELISA has been developed for determination of endotoxin coreantibodies in human plasma or serum in patients or healthy individuals. Several studies showa consistent drop in postoperative levels of circulating anti-endotoxin core antibodiescompared to the preoperative value. This drop has been interpreted as consumption ofantibodies to endotoxin by systemic release of endotoxin. A hypothesis is that if the patientspre-operative endotoxin-core level is low, even moderately low, patients may not be able tocope with the efflux of endotoxin, which may have mild to severe clinical consequences. Theassay is of interest for various experimental conditions ranging from in vitro LPSneutralization by plasma components to in vivo studies on kinetics of antibodies to endotoxinin health and diseases.The EndoCAb® standard median-units IgA (MU) are arbitrary and are based on medians ofranges for 1000 healthy adults in a particular locality. It has not been established whethernormal endotoxin-core antibody values vary by region, culture or race. Users shouldestablish appropriate local statistical controls for their studies. It is advised that studies of anypatient group should always be controled by studies of appropriately selected contrastingclinical groups and/or healthy individuals recruited locally.EndoCAb® is a registered trademark. Used under license from the Scottish National Blood TransfusionService.