1000 / 1 (>1 x 109 / L)(ii) < 20% of bone marrow blasts(iii) Peripheral (blood) blasts < 5%(iv) Presence of bone marrow dysplasiao CMML is also known as philadelphia chromosome negative leukemia.o CMML shares clinical and biological features with both myelodysplastic syndrome (MDS) and chronic myeloproliferative disorders (CMPDs), and may take on predominantly myelodysplastic (MD - CMML) or myeloproliferative (MP - CMML) characteristics.WHO diagnostic criteria for CMMLMajor criteria1. Persistent peripheral blood monocytosis > 100 / 12. Absence of philadelphia chromosome or BCR / Abl fusion gene.3. < 20% myeloblasts + tnonoblasts + promonocytes in peripheral blood or bone marrow4. Dysplastic changes in one or more myeloid lineages.Minor criteria1. Acquired clonal cytogenetic abnormality in bone marrow cells.2. Persistent monocytosis > 3 months, after exclusion of all other causes of monocytosis.o For the diagnosis of CMML all 4 major criteria must be present. In the absence of myelodysplasia, or when only minimal myelodysplasia is present, the diagnosis of CMML can be made when the first 3 criteria and at least one of the minor criteria are fulfilled.o CMML has been split into:- (i) CMML -1 < 10% bone marrow blastsCMML - 2 11-20% bone marrow blastsWHO criteria for the classification of CMMLCMML -1Bone marrow blasts < 10%Peripheral blood blasts < 5%CMML-2Bone marrow blasts 10-19%Peripheral blood blasts 5-19%OR : Presence of Auer rods when blasts in peripheral blood and bone marrow < 20%CMML -1 or CMML -2 with eosinophiliaAbove criteria for CMML - 1 or CMML - 2 ANDPeripheral blood absolute eosinophil count >1500 / 1">