> Information Center > Technical FAQs > Antibody Technology Column > What is Antibody AffinityAntibody affinity refers to the strength with which the epitope binds to an individual paratope (antigen-binding site) on the antibody. High affinity antibodies bind quickly to the antigen, permit greater sensitivity in assays and maintain this bond more readily under difficult conditions. Low affinity antibodies, by contrast, bind weakly to the antigen and often do not detect the antigen in-vivo or in assays.