Endotoxin observed in sera of dengue patients. (A) The levels of endotoxin in 37 randomly chosen samples were measured by ToxinSensorTM Chromogenic LAL Endotoxin Assay Kit (GenScript USA Inc., Piscataway, NJ). Two distinct patterns were observed in DF patients. A high range of endotoxin levels were observed in a fraction of DF patients and in DF patients with noticeable gut bleeding, while a subset of DF patients had endotoxin levels within the range of healthy controls. (B) The levels of endotoxin in general, increased with time, being higher on days 6 to 9 after onset of fever.