Variation in this arena, including training of the cord blood collection staff, may account for the differences in the volume collected and the rates of disqualification of units for contamination and other reasons.

Storage Methods

Most cord blood banks store units as a red blood cell-depleted product (also referred to as a mononuclear cell3 product) with the exceptions of ITxM Cord Blood services, the Sibling Donor Cord Blood Program, and StemCyte International Cord Blood Banks and Cord Blood Family Trust. The most popular anticoagulant and cryoprotectant agents were citrate-phosphate-dextrose (CPD) and dimethyl sulfoxide (DMSO), respectively. The majority of banks also indicated that they store the units in the vapor phase of liquid nitrogen.

There are limited data available relating to the viability of cord blood units stored long-term. Though research suggests that units can be stored for extended time frames (as many as 12 years) with no reduction in viability, proof of this concept is needed, and research into this area is critical (Broxmeyer, 1995).

Although some researchers argue that the vapor phase of liquid nitrogen is inadequate because the temperatures are slightly higher than those of liquid nitrogen itself and also allow for temperature variations when the lid of the storage container is opened, use of the vapor phase is substantially more economical, given the reduced liquid nitrogen needs, and this method also assists in the prevention of the spread of potential contaminants.

PROCESSING PROCEDURES

Screening Maternal Donors and Cord Blood

Cord blood acquisition must be done carefully because of the potential presence of transmissible diseases or pre-existing genetic conditions and possible contamination with maternal cells and microbial agents. As mentioned above, the collection and processing practices and procedures vary substantially among the cord blood banks. Both banks and transplant centers should use current best practices to ensure that the transplanted unit is safe and that everything possible has been done to ensure the success of the graft as well as the health of the patients who have received the graft.

Once consent for the collection of cord blood has been obtained (see the discussion of consent issues in Chapter 5), an extensive behavioral

3  

Includes precursors to white blood cell macrophages.



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