The Elek test is used for the detection of which toxin?

The Elek test is specifically designed to detect the toxin produced by Corynebacterium diphtheriae, the bacterium responsible for diphtheria. This test is a type of immunodiffusion assay that identifies the presence of diphtheria toxin in a clinical sample. In this test, an agar plate containing antibodies against the diphtheria toxin is inoculated with the suspected bacteria. If the bacteria produce the toxin, a visible precipitin line forms where the toxin diffuses towards the antibodies, indicating a positive result.

This test is crucial in confirming cases of diphtheria, particularly in individuals who may not have a characteristic clinical presentation, or in epidemiological studies investigating the presence of the organism and its toxin. The specificity of the Elek test for C. diphtheriae reinforces its vital role in microbiological diagnostics related to diphtheria.