[Biotin-avidin-ELISA for cytotoxin purified from cobra venom].

A technique combining the biotin-avidin amplifying system with sandwich enzyme-linked immunosorbent assay (B-A-ELISA) was developed for the microassay of the cytotoxin from Naja naja atra venom. The horse-peroxidase was used as the marker and polystyrene microhemagglutination plates as solid carrier. The sensitivity was 0.5 ng.ml-1. The assay range was 1.25-320 ngml-1 with coefficient of variation of 4.9% (intragroup) and 8.1% (intergroups), respectively.