A cartridge and method for conducting a labeled molecular affinity binding test such as antibody/antigen, ligand/receptor, and colorometric reactions, and other chemical reactions for which one or more analytes is present in a liquid sample formate. A progressive compression structure progressively forces a liquid flow out of a conjugate pad toward a reaction region to more thoroughly and rapidly mix the liquid, encouraging specific first affinity binding to the analytes in question. A specially dimensioned constricting passageway surrounding the reaction region including the result zones provides an additional siphoning force to the flow. These combined forces rapidly and more evenly guide the flow of liquid through the reaction region so that the rushed rate of uptake of analytes at the strip lines are more evenly distributed, adhesive attachment of non-specific molecules is largely avoided, vastly improving sensitivity and specificity, and providing quantitative results in some tests.