title: Does the time between collecting and processing umbilical cord blood samples affect the quality of the sample?
abstract: OBJECTIVE
  To assess the association between the time from umbilical cord blood collection until processing and the quality of the sample.
  
  
  METHODS
  Umbilical cord blood samples collected during the third stage of labor were placed in temperature-controlled boxes for the transport of biological material and sent to an umbilical cord blood bank, where the number of nucleated cells, viable cells and CD34+ cells were counted, and samples were additionally tested for contamination at the following time intervals: up to 24 hours, up to 48 hours and up to 72 hours following sampling. Data were analyzed using the multivariate analysis of variance (MANOVA) and compared using McNemar's χ2 test. Significance was defined at p < 0.05.
  
  
  RESULTS
  Means and medians of the number of nucleated cells, viable cells and CD34+ cells decreased significantly (p < 0.0001) as a function of the increased time between sampling and analysis, the difference between 24 and 48 hours being less than the difference between 24 and 72 hours. A linear correlation was found between the mean number of viable cells and CD34+ cells at the three moments of analysis. Contamination testing was negative in all samples.
  
  
  CONCLUSIONS
  The increase in time interval from sampling until analysis negatively affected the number of nucleated cells, viable cells and CD34+ cells but was not associated with specimen contamination. A linear correlation was found between decrease in the number of viable cells and CD34+ cells.
authors.affiliation: Universidade Estadual de Campinas - UNICAMP, Campinas, SP, BR.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Barini
authors.affiliation: Department of Medicine, Univesidade de Taubaté - UNITAU, Taubaté, SP, BR.
authors.forename: Ubirajara Costa
authors.initials: UC
authors.lastname: Ferraz
authors.affiliation: Department of Medicine, Univesidade de Taubaté - UNITAU, Taubaté, SP, BR.
authors.forename: Gregório Lorenzo
authors.initials: GL
authors.lastname: Acácio
authors.affiliation: College of Medical Science, Universidade Estadual de Campinas - UNICAMP, Campinas, SP, BR.
authors.forename: Isabela Nelly
authors.initials: IN
authors.lastname: Machado