After the cells have been separated, the unit containing stem cells is mixed with a cryopreservation solvent. This solvent protects the cells against the formation of ice crystals, which can rupture the cell membrane. The solvent most commonly used for cryopreservation of cord blood is "DMSO" (Dimethyl Sulfoxide).

To further protect cord blood cells against the formation of ice crystals, it is important that the cells freeze slowly. This is done in a special controlled-rate freezer, and then the blood is transferred to long-term storage. The final storage temperature should remain stable at -196 degrees centigrade.

LifeCell uses special compartmentalized cryo-bags to store your baby’s precious cord blood stem cells. The bag includes a 20 ml and 5 ml portion and three segments for testing. The cord tissue stem cells are stored in two 5 ml cryo-vials, which has an integrated segment for testing. The stem cells bags and vials are overwrapped for added protection and also to avoid cross-contamination. They are housed in protective cassettes and boxes and placed in liquid nitrogen storage vessles for cryogenic preservation at -196 degrees centigrade.

It is believed that stem cells can be successfully stored for decades in a cryo-preserved form. A recent study of cord blood at Indiana University demonstrated its viability after 15 years of cryogenic storage.