CD-Chex Plus is a positive procedural control for monitoring immunophenotyping by flow cytometry. It provides 30 assayed parameters including T-lymphocytes, B-lymphocytes, granulocytes, monocytes and NK cells. It is available in two clinically relevant levels of CD4+ cells and is assayed for a normal level of CD34+ cells. Designed to resemble a patient sample, CD-Chex Plus is manufactured from normal human peripheral blood leukocytes and erythrocytes. The whole blood control 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 Plus and CD-Chex Plus CD4 Low are available in plastic vials with pierceable caps for use with automated flow cytometry sample preparation instruments, reducing errors and improving laboratory workflow.