What are Frozen Red Blood Cells?

It is Packed RBC frozen with cryoprotective agents added to it to prevent cells lyse once they are thawed.

Cryoprotective agent - a solution that will protect the red cells from ultra low temperatures. 

Why Freeze Red Blood Cells?

• Shelf life is 10 years from day of collection 
• To store rare blood type
• To store autologous units
• To use in time of need, when there is a blood shortage

Procedure for Freezing RBCs:

1. A cryoprotective agent must be added to the red blood cells within 6 days of collection if the preservative is CPD or CPDA-1 and up to 42 days when preserved in AS-1, AS-3, and AS-5, except for rejuvenated RBCs.

Two categories of cyroprotective agents:

· Penetrating agent – (ex: glycerol) this involves small molecules that cross the cell membrane into the cytoplasm. The osmotis force of the agent prevents water from migrating outward as extracellular ice is form, preventing intracellular dehydration.

· Non-penetrating agent – (ex: hydroxyethyl starch or HES) this comprises large molecules that do not enter the cell but instead form a shell around the cell, preventing loss of water and subsequent dehydration.

2. The cryoprotective agent must be introduced to the RBCs very slowly or it will damage the cells.

3. The storage bag must be a chloride or polyolefin bag to survive the storage temperature and prevent leakage.

4. After the addition of cryoprotective agent, the unit is ready to freeze at -65C or colder.

5. For more details on this procedure, please refer to the AABB Technical Manual.

When can you freeze RBCs:

• RBCs preserved in CPD or CPDA-1 may be stored at 1-6C for up to 6 days before freezing.
• RBCs preserved as AS-1, AS-3, and AS-5 may be stored at 1-6C for up to 42 days before freezing.
• RBCs that have undergone rejuvenation during storage or up to 3 days after expiration may be processed for freezing.

03/01/2005last reviewed/updated