[Standardization and Quality Control in Flow Cytometric Enumeration of CD34(+) cells]

The enumeration of CD34(+) cells by flow cytometry is commonly employed to assess hematopoietic stem/progenitor cells in cord blood, peripheral blood and apheresis products. Interlaboratory variation of CD34(+) cells enumeration is exceedingly large. Factors contributing to those variation, currently established flow cytometry protocols and comparison between these protocols were reviewed. CD34(+) cells in 45 cord blood samples, 12 normal bone marrows and 4 apheresis products were also enumerated in our laboratory by using ProCUNT kit, and results showed that the ProCUNT is highly standardizaed and could assist in reducing interlaboratory variation of CD34(+) cells.