Evaluating Otherwise-Discarded Umbilical Cord Blood as a Source for a Neonate's Complete Blood Cell Count at Various Time Points.

BACKGROUND

Previous studies have reported the use of cord blood for admission laboratory complete blood counts (CBCs). However, no studies have investigated its stability for the first 30 min after delivery.

OBJECTIVES

We quantified blood cells drawn from the umbilical vein to determine the effect of (1) the time after placental delivery, and (2) the site of blood sampling (umbilical vein on an isolated cord segment vs. umbilical vein on the placental surface).

METHODS

Timed phlebotomies were drawn at 2, 10, and 30 min from (1) the umbilical vein on an isolated, double-clamped cord segment, and (2) the umbilical vein near or on the placental surface. Leukocyte count, hemoglobin, platelet count, and fibrinogen were measured on each phlebotomy sample.

RESULTS

Blood drawn from the isolated umbilical cord segments had leukocyte count, hemoglobin, platelet count, and fibrinogen that remained unchanged between the phlebotomies at 2, 10, and 30 min after delivery. However, blood drawn from the umbilical vein on the placental surface had, at 30 min, a leukocyte count (p = 0.002), hemoglobin (p = 0.01), and platelet count (p = 0.001) that were statistically different from the values at 2 and 10 min after delivery. There was no difference in fibrinogen at 2, 10, or 30 min.

CONCLUSIONS

If cord blood is used for a neonate's initial CBC, the blood should be drawn within 10 min of the placental delivery when it is taken from the umbilical vein on or near the placenta. If an umbilical cord segment is obtained, the phlebotomy can be delayed for up to 30 min.