The endotoxin test is a gel clot assay used to determine whether the test samples contain specific amounts of endotoxin. The sample and the limulus amebocyte lysate (LAL) reagent solution are mixed in an endotoxin-free tube and incubated at 37°C for 60 min. After the incubation, the tube is tilted to check whether the mixture clots. If the sample contains less amount of endotoxin under the standard, the mixture remains liquid; while if the endotoxin amount is higher than the standard, the mixture will clot at the bottom of the tube.
