[Plasma endotoxin assay by supersensitive reagent for the diagnosis of gram-negative bacteremia]

With a novel supersensitive reagent, we evaluated the utility of measuring plasma endotoxin level for the rapid and sensitive diagnosis of gram-negative bacteremia. Subjects were 112 febrile(more than 38 degrees C) patients suspected of having bacterial infection and 170 samples were collected. Venous blood was obtained aseptically before administering antibiotics. Blood culture and endotoxin assays were performed simultaneously with these materials. Plasma endotoxin levels were positive in 64 samples when the cut off index was postulated at 0.35 pg/ml, while only 5 samples when the cut off index was postulated at 5 pg/ml. When the cut off index was at 0.35 pg/ml, sensitivity was 86%, while it was 14% when the cut off index was 5 pg/ml. Gram-negative rods(GNR) were detected by blood culture in 14 cases and the average period to detect GNR was 14.8 hours. The presence of circulating viable bacteria is diagnosed by blood culture, but because of the serious consequence of bacterial sepsis, treatment is initiated even in the absence of an identifiable organism. Since plasma endotoxin level can be assayed in about 2 hours, it will be more practical if we adjust the cut off index according to the clinical situation.