A pinch wall and dam system for controlling fluid flow movement between a sample receiving pad and a test strip includes a sample receiving pad and a test strip in contact with the sample receiving pad. The 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. The pinch wall and dam system further includes a dam, sitting on top of the sample receiving pad, the dam preventing the backflow of fluid from an area near the first portion of the pinch wall.