Measurement of endotoxin in blood products using an endotoxin-specific limulus test reagent and its relation to pyrogenic activities in rabbit

Abstract

The amounts of endotoxin in commercial blood products were measured by the turbidimetric kinetic Limulus test with an ordinary reagent (LAL-HS) and a new endotoxin-specific reagent (LAL-ES). LAL-ES contains a sufficient amount of a water-soluble (1 {3)-β-D-glucan derivative as a blocker of the (1{3)-β-D-glucan-mediated coagulation pathway in the reaction of the Limulus amebocyte lysate. The amounts of endotoxin in alubumin and globulin products measured with LAL-ES agreed with pyrogenic activities in rabbits, but those measured with LAL-HS did not. Added endotoxin in the blood products was well recovered with LAL-ES, but that in some products was excessively recovered with LAL-HS. The amounts of endotoxin in diphtheria-pertussis-tetanus combined vaccines measured with LAL-HS and LAL-ES agreed with the pyrogenic activities in rabbits. The results suggested the existence of a false-positive substance like β-glucan in the blood products but not in the vaccine. LAL-ES is more suitable for the detection of endotoxin in blood products than LAL-HS.