Abstract: A competitive immunoassay, dye and method for rapidly detecting the presence of one or more target ligands within a fluid sample suspected of containing such ligand or ligands. The immunoassay comprises a protein-binding membrane, a first absorbent pad, a second absorbent pad, and a third absorbent pad. The protein-binding membrane has at least two regions of antibodies bound thereto for detecting dissimilar ligands. The second absorbent pad has formed therein a colloidal gold tracer having one, and preferably two or more ligand analog protein complexes adhering thereto. To utilize the system, the immunoassay strip is placed within a fluid sample. To the extent the target ligand is absent, a visual indicator will be provided signaling such absence. To the extent the target ligand is present at or above a threshold level, no such visual signal will be produced.

Abstract: A competitive immunoassay, dye and method for rapidly detecting the presence of one or more target ligands within a fluid sample suspected of containing such ligand or ligands. The immunoassay comprises a protein-binding membrane, a first absorbent pad, a second absorbent pad, and a third absorbent pad. The protein-binding membrane has at least two regions of antibodies bound thereto for detecting dissimilar ligands. The second absorbent pad has formed therein a colloidal gold tracer having one, and preferably two or more ligand analog protein complexes adhering thereto. To utilize the system, the immunoassay strip is placed within a fluid sample. To the extent the target ligand is absent, a visual indicator will be provided signaling such absence. To the extent the target ligand is present at or above a threshold level, no such visual signal will be produced.

Abstract: A competitive immunoassay and method for rapidly detecting the presence of one or more target ligands within a fluid sample suspected of containing such ligand or ligands. According to a preferred embodiment, the immunoassay comprises an elongate adhesive-coated plastic support onto which are formed a protein-binding membrane, a first absorbent pad, a second absorbent pad, and a third absorbent pad. The protein-binding membrane has two regions of antibodies bound thereto, one antibody being specific to the target ligand, and the other as a test control. The second absorbent pad comprises a high capacity absorbent having formed therein a freeze-dried colloidal gold tracer, and may further include a control reagent for binding with the test control antibodies. To utilize the system, the immunoassay strip is placed within a fluid sample. To the extent the target ligand is absent, a visual indicator will be provided signalling such absence.