CD-Chex CD34 is a ready-to-use, positive procedural control for enumerating CD34 positive cells by flow cytometry. Designed to mimic a patient sample, CD-Chex CD34 contains human leukocytes and erythrocytes in a preservative medium with CD34 positive cells having characteristics similar to human hematopoietic progenitor cells. The whole blood control does not need to be diluted and offers 30-day open-vial stability, eliminating the need to track thermal openings. Its long shelf life reduces the number of shipments, associated costs and time spent performing lot-to-lot correlation. CD-Chex CD34 is compatible with flow cytometry systems using ISHAGE gating strategies for enumeration of CD34 cells and these commercially available enumeration kits: BD Biosciences ProCOUNT Progenitor Cell Enumeration Kit, BD Stem Cell Enumeration Kit and Beckman Coulter Stem-Kit. It is the only stem cell control for CD34+ positive cells that offers three levels.