Enzyme treatment of red blood cells: use of ficin and papain.

Proteolytic enzymes are used to treat red blood cells (RBCs) to aid in complex antibody identification. Although there are many enzymes that can be used, for the purpose of this method review, enzyme-treated RBCs refers only to RBCs treated with ficin or papain. Ficin and papain can increase the sensitivity of antibody detection by modifying the RBC membrane. Enzyme treatment and test methods can be performed using one-stage or two-stage procedures. Enzyme treatment is especially useful for the differentiation of multiple antibodies, enhancement of detection of weak antibodies, and adsorption methods. In all cases, quality control is required to ensure adequate treatment of RBCs before additional testing. Ficin and papain are useful tools for both immunohematology reference laboratories and transfusion services.