A pinch wall system for controlling fluid flow movement between a sample receiving pad and a test strip, comprising: a sample receiving pad; a test strip in contact with the sample receiving pad; and a pinch wall positioned to sit directly on top of the sample receiving pad, the pinch wall configured to compress the sample receiving pad, the pinch wall comprising: a first portion separating a sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned adjacent to the test strip, and a second portion separating the sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned away from the test strip, wherein the sample receiving portion of the sample receiving pad that receives a sample thereon is positioned on an opposite side of the pinch wall from the portion of the sample receiving pad positioned away from the test strip, wherein the first portion of the pinch wall is configured to compress the sample receiving pad to a lesser degree than the second portion of the sample receiving pad so that fluid seeps more quickly under the first portion of the pinch wall than under the second portion of the pinch wall, such that the test strip becomes saturated prior to excess fluid being absorbed in the portion of the sample receiving pad away from the test strip such that the test strip does not become flooded, the portion of the sample receiving pad positioned away from the test strip being sufficiently sized to absorb the excess fluid. a sample receiving pad; a test strip in contact with the sample receiving pad; and a pinch wall positioned to sit directly on top of the sample receiving pad, the pinch wall configured to compress the sample receiving pad, the pinch wall comprising: a first portion separating a sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned adjacent to the test strip, and a second portion separating the sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned away from the test strip, wherein the sample receiving portion of the sample receiving pad that receives a sample thereon is positioned on an opposite side of the pinch wall from the portion of the sample receiving pad positioned away from the test strip, wherein the first portion of the pinch wall is configured to compress the sample receiving pad to a lesser degree than the second portion of the sample receiving pad so that fluid seeps more quickly under the first portion of the pinch wall than under the second portion of the pinch wall, such that the test strip becomes saturated prior to excess fluid being absorbed in the portion of the sample receiving pad away from the test strip such that the test strip does not become flooded, the portion of the sample receiving pad positioned away from the test strip being sufficiently sized to absorb the excess fluid. a first portion separating a sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned adjacent to the test strip, and a second portion separating the sample receiving portion of the sample receiving pad from a portion of the sample receiving pad positioned away from the test strip, wherein the sample receiving portion of the sample receiving pad that receives a sample thereon is positioned on an opposite side of the pinch wall from the portion of the sample receiving pad positioned away from the test strip, wherein the first portion of the pinch wall is configured to compress the sample receiving pad to a lesser degree than the second portion of the sample receiving pad so that fluid seeps more quickly under the first portion of the pinch wall than under the second portion of the pinch wall, such that the test strip becomes saturated prior to excess fluid being absorbed in the portion of the sample receiving pad away from the test strip such that the test strip does not become flooded, the portion of the sample receiving pad positioned away from the test strip being sufficiently sized to absorb the excess fluid.