Abstract
A modified Elek test and an immuno-halo test were developed for detection of the thermostable direct hemolysin produced by Kanagawa phenomenon-positive strains of Vibrio parahaemolyticus. The sensitivity of the modified Elek test was almost the same as that of the Kanagawa phenomenon on Wagatsuma medium, and the results of both reactions correlated very well. The immuno-halo test was a little less sensitive than the modified Elek test. Since the Kanagawa phenomenon on Wagatsuma medium sometimes give false-positive results due to instability of the blood used in the medium, we recommend the immunological techniques described here as reproducible methods for identification of the thermostable direct hemolysin by V. parahaemolyticus.