Proteins can be detected in a biological sample using which test?

In the context of detecting proteins in a biological sample, the Western blot is a highly effective technique. This method specifically allows for the identification and quantification of proteins by separating them based on their molecular weight through gel electrophoresis. Following this separation, the proteins are transferred to a membrane and then targeted with specific antibodies that bind to the protein of interest. This step is crucial, as it provides a means to visualize the proteins, typically through a secondary antibody that produces a detectable signal.

While other techniques mentioned, such as ELISA, are indeed used for protein detection, they are not structurally aligned with the Western blot method which combines separation and transfer processes unique to Western blotting. Southern blotting and PCR, on the other hand, are techniques specifically designed for DNA analysis, making them unsuitable for direct protein detection. Thus, the Western blot stands out as the appropriate and specialized method for the detection of proteins in various biological samples.