CD-Chex TdT Plus®

CD-Chex TdT Plus is a ready-to-use positive procedural control for evaluating CD2, CD4, CD5, CD7, CD8, CD34, cytoplasmic CD3 and nuclear TdT (terminal deoxynucleotidyl transferase) expression by flow cytometry. This control contains an abnormally high CD34+ population (over 60% positive) and several markers designated as “rare flow antigens” by CAP.

CD-Chex TdT Plus is the only flow cytometry control assayed for TdT, CD1a, CD34 and cytoplasmic CD3. These markers are critical for diagnosing and classifying acute lymphoblastic leukemias and lymphomas, and having a ready-to-use control eliminates the need to hold and validate patient samples for quality control purposes.

CD-Chex TdT Plus offers an abnormally high level of CD34+ cells (over 60%) to resemble acute leukemia patient samples where blast populations are elevated. This high CD34+ level allows laboratories to monitor performance of immunophenotyping panels used for leukemia diagnosis and classification.

TdT (terminal deoxynucleotidyl transferase) is a nuclear enzyme expressed in immature lymphoid cells. It is a key marker for diagnosing acute lymphoblastic leukemia and distinguishing lymphoid from myeloid lineage in acute leukemias. CD-Chex TdT Plus provides a control for this critical intracellular marker, ensuring proper staining and detection of TdT-positive cells.

CD-Chex TdT Plus offers 30-day open-vial stability and 90-day closed-vial stability. This extended stability reduces the frequency of lot-to-lot correlations and shipments, saving time and resources while maintaining consistent quality control performance.

CD-Chex TdT Plus is compatible with BD Biosciences and Beckman Coulter flow cytometry systems. Users also have access to manufacturer established assay ranges (no need to verify range per CAP requirements) and STATS, Streck’s free interlaboratory quality control program for peer group data comparison.

Nuclear TdT requires specialized fixation and permeabilization procedures to allow antibodies to penetrate the cell and nuclear membranes while preserving antigen integrity and cell morphology. CD-Chex TdT Plus challenges this entire technical process, ensuring that laboratories can properly detect this critical nuclear marker. The control verifies that fixation protocols, permeabilization steps and nuclear antibody staining are all functioning correctly.

CAP requires quality control for rare flow antigens and complex immunophenotyping panels used in leukemia diagnosis. CD-Chex TdT Plus provides defined assay values for multiple rare markers including nuclear TdT and cytoplasmic CD3, along with surface markers critical for acute leukemia classification. The manufacturer established assay ranges eliminate the need for range verification per CAP requirements, and the abnormally high CD34+ population ensures the control challenges leukemia-relevant immunophenotyping workflows.