A New Perchloric Acid Treatment of Human Plasma for Detection of Endotoxin by an Endotoxin-Specific Chromogenic Test

Abstract

Recently, an endotoxin-specific colorimetric assay method, using synthetic chromogenic substrate, was developed using factor G-depleted lysate (Endospecy, Seikagaku Kogyo)(3). Since many interfering factors and inhibitors of Limulus amebocyte lysate test are present in human plasma, it became necessary to remove these prior to the detection of endotoxin. Perchloric acid (PCA) treatment of human plasma has been used to inactivate or remove the interfering factors (2). In this method, PCA is added to test plasma and the mixture is incubated. The precipitate is discarded after centrifugation. The supernantant is employed for detection of endotoxin using Endospecy. We have found, however, that a large amount of endospecy activity was recovered from the precipitate, and we developed an improved method of PCA treatment by which endotoxin content in both the precipitate and supernatant could be measured.