The sample pad can have multiple roles, the most important of which is to evenly distribute the sample and to direct it to the conjugate pad.The sample pad is usually impregnated with buffer salts, proteins, surfactans and other liquids to control the flow rate of the sample and to make it suitable for the interaction with the detection system. Moreover, the pores of the sample pad can act as a filter in order to remove redundant materials, e.g. red bloos cells. 

Glass cellulose membrane:Glass fiber membrane can be used as a conjugate release pad or sample pad. The conjugate relese pad.

sample pad:The sample pad receives the sample and equably transports it to conjugate release area or analytical membrane. The specific transport location depends on the structure of the test device. It also has the function of filtering particulate matter and cells from the sample.