61 initial samples with FLT3 ITD positive by both methods were collected from AML patients, including AML with mutated NPM1 (n = 24), AML with maturation (n = 14), AML with myelodysplasia-related change (n = 5), acute myelomonocytic leukemia (n = 5), AML with biallelic mutation of CEBPA (n = 3), acute promyelocytic leukemia (n = 3), AML with mutated RUNX1 (n = 2), AML with t (8;21)(q22;q22.1) (n = 2), acute monocytic leukemia (n = 2) and AML with inv. The gene discussed is NPM1; the disease is acute promyelocytic leukemia.