The expansion and persistence of CAR T cells within patients is the key to a successful treatment. Therefore, monitoring of CD19 CAR T cells following infusion is of utmost interest. The CAR detection reagent is the most critical reagent for CAR T cell flow cytometry assays. When selecting a strategy for CAR detection, the impact of the reagent on the assay specificity and reliability must be taken into consideration. Join Dr. Sabine Hünecke and Dr. Melanie Bremm from University Hospital Frankfurt and Dr. Annika Graband from Miltenyi Biotec to learn about