Terminal transferase expression in the differential diagnosis of acute leukemias. Eastern Cooperative Oncology Group

While the clinical significance of terminal transferase (TdT) detection in acute lymphoblastic leukemia (ALL) is uncontested, conflicting evidence exists for the prognostic relevance of this enzyme in blast cells from patients with acute myeloid leukemia (AML). The technical challenge of determining TdT in myeloid blast cells may be primarily responsible for those discrepancies in the literature. We present here the relative values of various standard approaches to the detection of TdT in ALL versus AML, including the slide staining technique, which served as the reference method, flow cytometry, and the biochemical enzyme assay.