Comparison of Umbilical Cord Collection Methods: Impact on Cellularity and Microbial Contamination Rates.

Abstract

IntroductionUmbilical cord blood collections are typically performed using one of two methods: the syringe collection method and the gravity collection bag method. Collection volume, total nucleated cell (TNC) count, total CD34 positive cell count and percent with microbial contamination were analyzed to determine differences between collections performed using these two methods.MethodsUnits were processed using a hydroxyethyl starch red blood cell depletion method. TNC counts were measured using a Beckman Coulter HmX Analyzer. Total CD34 positive cell counts and viability were measured using the Beckman Coulter Epics XL-MCL flow cytometer. Microbial testing was performed using the VersaTrek system. Data related to collection volume and cellular content were analyzed by a Wilcoxin rank sum test of the paired differences [95% confidence interval (CI) for the difference between the control and experimental (syringe collections) results].Results and ConclusionsThe total cord blood volume collected via the syringe method was not significantly lower than that collected using the gravity collection bag method. However, the TNC count and total CD34 positive cell count from syringe collections were significantly inferior to the TNC count and CD34 positive cell count from gravity bag collections. The rate of microbial contamination of units collected in syringes was 3.3-fold higher than that of units collected using gravity collection bags. Cord blood banks should train collection sites on optimal collection methods and monitor the compliance of all collection sites with standardized collection procedures.Summary of ResultsGravity Bag CollectionsSyringe CollectionsCollection VolumeN27,12155Mean66 mL60 mLStandard Deviation+/− 30 mL+/− 24 mLWilcoxin rank sum test (p-value)0.0945TNC Count (Post Processing)N27,12155Mean7.5 x 10^85.0 x 10^8Standard Deviation+/− 4.6 x 10^8+/− 3.5 x 10^8Wilcoxin rank sum test (p-value)<0.0001Total CD 34 Positive Cells (Post Processing)N20,49551Mean2.76 x 10^61.77 x 10^6Standard Deviation+/− 2.87 x 10^6+/− 1.32 x 10^6Wilcoxin rank sum test (p-value)< 0.0001Microbial Contamination Rate7.1 %23.6%