2. A diagnosis of JMML is confirmed only if the following criteria for JMML are met: a) ALL of the following: Absence of t(9;22) or BCR-ABL by PCR or FISH; Absolute monocyte count >1000 (1 X 109/µL); <20% bone marrow blasts; b) At least 2 of the following: Elevated Hb F hemoglobin; Myeloid precursors in peripheral blood; WBC >10,000 (10 X 109/µL); GM-CSF hypersensitivity in methylcellulose culture of bone marrow progenitors cells.