Freezing and recovering rare red blood cells using liquid nitrogen

Rare red blood cells (RBCs) can be used to resolve reactivity in antibody identification or compatibility testing. Because these RBCs are usually not readily available, when identified in donors or patients, a quick and easy method for long-term storage is needed. By freezing in liquid nitrogen, injury to the RBCs is prevented, and rendering them usable for testing takes only a few washes.