The glass fiber can be used as a conjugate pad and a sample pad. For the conjugate pad, antibodies are combined with colloidal gold, colored or fluorescent latex microspheres, or magnetic bead complexes. Effective chemicals, surfactants and other components are treated on the surface of the glass cellulose through relevant processes, and are effectively released when the sample flows through the conjuage pad.

The sample pad is used to receive the sample and transfer it to the area of the conjugate pad. Then, the sample flows through the membrane and finally reaches the absorbent paper. The specific transfer position varies depending on the structure of the detection device. Some sample pads also have the functions of filtering particulate matter and red blood cells.