Abstract: A multizone test device for the determination of analyte in a liquid test medium. The test device preferably comprises multilayers including a first layer comprising a solid, porous matrix incorporated with a reversibly immobilized first reagent and a second layer comprising a solid, porous matrix incorporated with a second reagent which interacts with the first reagent and analyte from the liquid test medium to provide a detectable signal. A reversible binding interaction between the first reagent and the matrix of the first layer prevents the first reagent from prematurely migrating into the second layer during manufacture of the device and prior to application of the liquid test medium to the test device. The reversible binding interaction is sufficiently disruptable by contact of the first layer with the liquid test medium to release and thereby render diffusible an analytically effective amount of the first reagent within the test device.