Diagnostic Kit for Carcino-embryonic Antigen (CEA) is a double antibody sandwich immunoassay kit for the quantitative testing of Carcino-embryonic Antigen in blood. The membrane was precoated with CEA specific antibodies on the test band region and goat anti mouse IgG on the control band region. During the test, the specimen is allowed to react with CEA specific antibodies-colloidal gold particles conjugate, which was predried on the test strip.The conjugate binds to the CEA forming an antibody-antigen complex. The complex moves forward on the membrane by the capillary action, then the complex is captured by CEA specific antibody on the test region to produce a visual pink color band. The color band is positive correlated with the concentration of CEA of the specimen. Regardless of the presence of CEA, as the mixture continues to move across the membrane to the control band region, the complex is captured by immobilized goat anti mouse antibodies to form a distinct pink colored control band.