Description(s):
Carcinoembryonic antigen (CEA) is a glycoprotein produced in gastrointestinal tissue during fetal development. This protein is usually present at low levels in the blood of healthy adults. However, CEA levels in the serum are elevated in some types of cancer, making it an effective tumor marker in clinical tests. CEA is commonly measured to monitor patients with colon cancer.
Principle
The wells of the plate are coated with capture antibody specific to CEA. In this assay, the test sample initially reacts with the solid phase capture antibody, resulting in CEA being bound to the well. The wells are then washed to remove unbound proteins, and biotin-linked antibodies are added to bind to the immobilized CEA. After washing away the unbound antibodies, Streptavidin-HRP conjugate is added to form a complex with the antibody-bound CEA. After incubation, the wells are washed to remove unbound Streptavidin-HRP conjugate. TMB substrate is then added and forms a blue color when the HRP-linked antibodies are detected. The reaction is then terminated with Stop Solution, which changes the color from blue to yellow. The CEA concentration in each well is directly proportional to its color intensity and can be quantified by measuring its optical density at 450 nm (OD450) in a microplate reader.
