ASSAY METHOD, TEST DEVICE AND KIT FOR SPECIFIC BINDING LIGAND WITH FLOW VELOCI- TY ADJUSTED THROUGH FILTER FILM

PURPOSE: To reduce background and improve assay sensitivity by adjusting the average pore size of a membrane and the density or hydrophilic property of absorptive inner body so as to reduce flow velocity of a cleaning solution. CONSTITUTION: A micro porous filtering membrane 16 for filtering a fluid flowing from an upper reaction section chamber 12 to a lower fluid collecting section chamber 14 is brought into contact with an absorptive inner body 30 for absorbing a fluid passing through the membrane 16 by means of fluid, and the average pore size of the membrane 16 and the density or hydrophilic property of the inner body 30 are adjusted so that the cleaning time for fluid by using the membrane 16 may become 20 seconds. In general, the average pore size of the membrane 16 is about 0.1 to 3μm, 1.2μm preferably, and the density of the inner body 30 made of fiber and sponge material, etc., is 1.2 to 2.5g/cm in general. In this time, it is more important to adjust the pore size of the membrane 16, however, when the adjustment is impossible or not effective, the inner body 30 is adjusted to attain a desired low flow velocity.