Evaluation of enzyme-linked immunosorbent assay (ELISA) kit for paralytic shellfish poisoning toxins

The reliability and utility of an enzyme-linked immunosorbent assay (ELISA) kit for paralytic shellfish poisoning (PSP) toxins were examined. Compared with the mouse bioassay, which is an official method worldwide, as described by the Association of Official Analytical Chemists (AOAC), the system showed remarkable sensitivity to saxitoxin (STX). The recovery of saxitoxin diacetate (STX-A) from clam meat was almost 100% over a certain range of the toxin concentration. However, the kit exhibited unpredictable cross-reactivities to a mixture of gonyautoxins (GTXs), and underestimated the toxicity of some naturally contaminated shellfish samples which were harvested in the sea near Japan. We consider that the existing mouse bioassay can not be replaced with the ELISA kit for the purpose of screening inshore shellfish samples. Considering the advantages of this method, however, the kit should be available for certain uses provided that its limitations are borne in mind.