Collection

Optimal yield of mononuclear cells remains a critical factor in UCB collection. A suitable UCB unit has been defined as a volume of at least 40 ml (excluding anticoagulant) and a total nucleated cell (TNC) count of 6 X 10.814 Factors associated with improved UCB harvest include fewer previous births, larger infant size, greater gestational age, longer umbilical cord, and larger placenta.1516 Two methods of UCB collection exist in utero and ex utero. In utero collection is initiated within seconds of delivery of the baby but prior to expulsion of the placenta. The umbilical cord is clamped, transected, and disinfected. The umbilical vein is then punctured with a 16-gauge needle connected to a standard closed blood donor collection system (450 ml) containing approximately 20-30 ml of CPDA (citrate, phosphate, dextrose, adenine) anticoagulant, and drained by gravity. Ex utero UCB collection takes place immediately following placental delivery. The delivered placenta is placed in a plastic-lined absorbent cotton pad suspended from a support frame. Within minutes, the disinfected umbilical cord vein is punctured and drained into a blood donor set containing CPDA anticoagulant. The method of collection varies between UCB banks and among collection sites within UCB banks. A small, randomized singleinstitution trial detected a statistically significant increase in mean volume (83.26 ml vs. 48.42 ml) and mononuclear cell numbers (3.12 X 108vs. 1.806 X 108) with in utero collection.17 This was supported by a retrospective single-institution analysis.18 A large, retrospective multicenter analysis of five programs established by the American Red Cross Cord Program argued equivalency between in utero and ex utero methods.19

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