A comparison of methods of removing inhibitors to the chromogenic Limulus assay in normal and jaundiced blood.

A comparative study was performed of methods of removing inhibitors to the quantitative chromogenic method of Limulus assay for endotoxin in normal and jaundiced plasma. Chloroform treatment failed to remove inhibitors in normal and jaundiced plasma and did not prevent inhibition of colorimetry by bilirubin. Perchloracetic acid (PCA) treatment decolourised jaundiced samples but gave unreliable results due to poor pH control. Boiling and dilution gave reliable results in jaundiced and normal plasma without significant loss of sensitivity and is the method of choice.