Streck, Omaha, Neb, has introduced CD-Chex TdT Plus, the only commercially available flow cytometry control assayed for terminal deoxynucleotidyl transferase (TdT), cluster of differentiation 1a (CD1a), CD34, and cCD3 in a single control. It can be used in the evaluation of such intracellular and surface antigens as CD1a, CD2, CD4, CD5, CD7, CD8, CD34, cytoplasmic CD3, and nuclear TdT. When stained with fluorescent antibodies and analyzed by flow cytometry, CD-Chex TdT Plus provides reference values for abnormal cells often found in certain types of hematopoietic neoplasms. Designed for use on BD Biosciences and Beckman Coulter flow cytometry systems, the control has a 30-day open-vial stability and up to a 90-day closed-vial stability. It is available for research use only. For more information, visit Streck.