Immunochemical techniques are vital in diagnostic and clinical applications. They are used to detect the presence and distribution of a target antigen in tissues and cells and in the diagnosis of infectious diseases. 

There are several immunochemical techniques you can choose from but not all can be used to identify a specific antigen or antibody. To choose the right immunochemical technique for your assay, you should consider these three factors: 

1. The conditions under which the experiment is being conducted. This includes the type of sample collected as well as the nature and place of work. 
2. The sensitivity and selectivity of the immunochemical technique to that specific sample. 
3. The nature of the reagents you’re using. Make sure the quality of your reagent is standardized, analyzed, and studied.