The COC Gold Rapid Screen Test Cassette is a chromatographic absorbent device in which drug or drug metabolites in a sample compete with drug antigen immobilized on a porous membrane support for limited antibody sites. Labeled antibody-dye conjugate mixes with sample specimen and binds to the free drug presented in sample forming an antibody-antigen complex. This complex prevents the formation of pink color bands in the test zone immobilized antigen conjugate when the drug is presented in the sample urine above the detection levels (300ng/ml for Cocaine). Unbound dye conjugate binds to the reagent in the control zone and produces a pink-rose color band, demonstrating that the reagents and device are functioning correctly. A negative specimen produces two distinct color bands, one for the control in the “C” zone and one for Cocaine in the “T” zone.