Abstract: A chromatographic immunoassay test strip comprising of a solid support having the portions with said portions being in a strip so as to permit capillary flow communication with each other based on the principle of “Bridge-Sanwhich”. In this chromatographic immunoassay test strip herein the analyte in the sample reacts with the ligand to form “ligand A-analyte-ligand B/tracer” first, then is captured by a bridge immobilized on the test zone of solid phase to form a complex of “bridge-ligand A-analyte-ligand B/tracer” which can be detected by vision or equipment.

Abstract: A chromatographic immunoassay test strip comprising of a solid support having the portions with said portions being in a strip so as to permit capillary flow communication with each other based on the help of adding a Buffer. This chromatographic immunoassay test strip herein changes the reaction order of the conventional chromatographic immunoassay solid test strip, wherein the analyte in the sample reacts with the specific binder (ligand A) immobilized on test zone prior to reacting with the ligand B/tracer. The reaction communication herein is achieved by a capillary flow aided by a Buffer. This solid chromatographic immunoassay test strip is useful in a variety of immunoassays.