Single radial immune hemolysis test for detection of Escherichia coli thermolabile enterotoxin

A single radial immune hemolysis test for the detection of thermolabile enterotoxin has been developed for routine purposes. Stationary cultures from enterotoxigenic Escherichia coli in Casamino Acids-yeast extract medium may be used for the detection of this enterotoxin, and under the conditions of the experiment, the single radial immune hemolysis test was as sensitive as the passive immune hemolysis test. The results obtained in the single radial immune hemolysis test agreed entirely with those obtained in the passive immune hemolysis test, and no false-positive reactions were obtained when cholera antitoxin diluted 1:80 was used. The assay is easy to perform, inexpensive, and specially designed for less-equipped laboratories.