Elek's gel precipitation test used for diagnosing:
Corynebacterium Jakeium
Corynebacterium diphtheriae
Clostridium tetani
Clostridium perfringens
Elek's gel precipitation test is an example of double diffusion in two dimensions. It is used to demonstrate C. dipthariae. Precipitation band: If the strain is toxigenic, the toxin diffuses in the agar, meets with the antitoxin and produces arrow-shaped precipitation band. Nontoxigenic stain will not produce any precipitation line. The precipitate lines would fuse with each other if the toxins produced by die strains are identical.
JIPMER 2019