We observed that IDH1/2 VAF in morphologic leukemia free state was not reduced below 2.5% in 15 out of 62 cases (24%, 10 IDH2 R140Q, 3 IDH2 R172K, 1 IDH1 R132H and 1 IDH1 R132C). The gene discussed is IDH1; the disease is leukemia.