The NC Membrane, which stands for, Nitrocellulose Membrane, serves as the support medium to immobilize the pre-coated antibody of the monoclonal antibody pair and the anti-IgG antibody (which serves as the control line in the rapid test). The location of the pre-coated antibody is termed the capture line, for it binds to the same antigen as the conjugated gold colloidal antibody and holds the antigen-antibody complex stationary thus, accumulates the visible red color of the gold colloid to indicate a positive result. The NC Membrane component of the strip is typically 3-4mm in width and 18 – 19 mm in length on a test strip.