The CEA test measures the level of carcinoembryonic antigen (CEA) in the blood.CEA is a protein normally found in the tissue of a developing baby in the womb. The blood level of this protein disappears or becomes very low after birth.he CEA test measures the level of carcinoembryonic antigen (CEA) in the blood.
Blood is made up of cells in a watery base, called plasma. There are three major types of cells blood made up of â red blood cells (RBCs), while blood cells (WBCs) and platelets. 1  They are also known as erythrocytes, carry oxygen to various parts of the body.  They are the most in number, constituting about 40-45% of blood. Their structure is like that of dough nuts.
Blood is a specialized body fluid. It has four main components: plasma, red blood cells, white blood cells, and platelets. The blood that runs through the veins, arteries, and capillaries is known as whole blood, a mixture of about 55 percent plasma and 45 percent blood cells.