Which of the following enzymes is NOT used in blood bank procedures?

• A. Ficin
• B. Bromelin
• C. Aldomet
• D. Trypsin

Answer: (C)

Enzyme treatment of red cells is used in blood banking to modify the cell surface and alter antigen expression, helping to reveal or differentiate antibodies during antibody screening and crossmatching. Ficin and bromelin (plant-derived proteases) and trypsin (a protease) are classic enzymes applied to reagent cells for this purpose. They can enhance or diminish reactivity for certain antibodies, aiding interpretation of serologic tests.

Aldomet is methyldopa, a drug, not an enzyme. It doesn’t treat red cells in laboratory procedures and isn’t used to modify antigens in serologic testing. That’s why it’s the option that does not fit.