A combination of electrophoresis and double immunodiffusion is referred to as which immunological technique?

The correct answer is based on the definition and methodology of immunoelectrophoresis. This technique integrates both electrophoresis and immunodiffusion to identify and quantify specific proteins in a sample.

During immunoelectrophoresis, the proteins in a mixture are first separated by electrophoresis based on their charge and size. After separation, an antibody specific to the protein of interest is added, leading to a diffusion process where precipitin lines form as the antibodies encounter their corresponding antigens. This allows for both qualitative and quantitative analysis of proteins.

In contrast, the other techniques listed do not combine these two specific processes in the same manner. Western blotting, for example, involves the transfer of separated proteins to a membrane followed by detection with antibodies, while immunofixation specifically focuses on identifying and characterizing proteins from a mixed sample but does not include the electrophoresis step combined with immunodiffusion in the same way. ELISA is a different method entirely, primarily focused on protein or antigen quantification through a solid-phase immunoassay rather than utilizing gel-based techniques.

Thus, immunoelectrophoresis serves as the correct term for the combination of electrophoresis and double immunodiffusion, as it