history is undertaken to determine whether the mother is likely to belong to a group that engages in a behavior that might pose a health risk to the recipient of the banked cord blood unit (e.g., risky sexual behaviors or illicit drug use). In addition, maternal and family histories for inherited genetic disorders are taken. The unit is screened for bacterial, viral, and fungal infections through testing of specimens obtained from the unit before it is frozen. A portion of the cord blood specimen is generally frozen as separate segments that may or may not be attached to the main unit to allow further, more complete testing for infectious diseases or genetic disorders if the unit is identified to be useful for transplantation or is able to fulfill some other need.
Cord blood can be collected from the placenta at two different times. It can be collected after delivery of the baby but before the placenta has been delivered, or it can be collected in a separate room after the placenta has been delivered. In either case, after sterilization of the umbilical cord to minimize the possibility of contamination, a large-bore needle is used to drain the cord blood, which is placed into a closed bag containing an isotonic anticoagulant at a neutral pH (Rubinstein et al., 1995).4 The former method is generally performed by obstetrical staff (e.g. the physician, nurse, or midwife) as part of the delivery procedure, whereas the latter method is generally performed by trained technicians or nurses outside of the delivery room.
Collection methods that rely on individuals other than cord blood bank staff can offer the possibility of cord blood collection in remote locations, which could greatly expand the donor pool. However, means for the ongoing training of the collection personnel and the promotion of standard protocols would have to be developed to ensure the quality of the units.
Wall et al. (1997) found few differences in either the volumes collected or in the total cell counts of the units collected either before or after delivery of the placenta. Other studies reported higher volumes and CD34+ cell counts if collection was performed before the delivery of the placenta (Surbek et al., 2000; Solves et al., 2003). These variations may be due to the additional time involved in the ex utero collections, which allow the formation of microscopic clots, thereby reducing the number of cells available in the unit (Wong et al., 2001). Alternatively, uterine contractions after delivery of the fetus may enhance drainage of placental blood. Collection after delivery of the placenta results in no difference in the volumes of cord blood