▲ Positive sample Positie sample Negatie sample Negatie smple FIG. 6. The enzyme cleaves the substrate causing a color change FIG 5 Unbound labeled antibody is washed anway, and a colo of the substrate solution. The intensity of the color is quanti- dimetric sbstrate (e.g. d-nitrophenylphosphate of ATBS) is tated using a spectrophotometer and is proportional to the added mount of antibody present in the smpl 加入反应底物 显色加入反应底物 显色