Left shift of bone marrow image is a manifestation of basophilic leukemia, e.g., bone marrow image shows a large number of basophils and 5% of primitive cells. Basophilic neutrophils and late granulocytes are also elevated, with left shifted nuclei and coarse basophilic granules in the cytoplasm. Then, what tests should be done to confirm the diagnosis of left shift of bone marrow image? The following is a brief introduction: 1, blood picture, white blood cell count is generally (2.8~144)×109/L, occasionally up to 500×109/L, basophils can be increased at all stages, generally accounting for 20% to 100%; hemoglobin and platelet decrease. 2.Bone marrow image In addition to the increase of pro-granulocytes, a large number of basophilic granulocytes can be seen, generally accounting for 33%~99%, basophilic granulocytes stained with toluidine blue or sparkle blue, with a strong positive reaction, with a certain degree of specificity, and Auer microsomes are rarely seen in the leukemia cells; in the chloroacetate esterase staining, the normal basophilic granulocytes show a negative reaction, whereas the disease can show a positive reaction, but it can also be negative, Myeloperoxidase and Sudan black B negative or positive, periodic acid Schiff reaction negative, but also positive, and terminal deoxynucleotidyl transferase (TdT) positive or negative. Light microscopically, the degree of maturity of the primitive cells varies greatly from patient to patient. The nuclear appearance of the primitive cells ranges from round or oval to lobulated or deeply indented, the nucleoli are often conspicuous, the cytoplasm is sparsely to moderately cytoplasmic and slightly basophilic, and the cytoplasm of some primitive cells contains vacuoles. Mature basophils were rare or absent; sometimes neutrophils were mildly abnormal and mildly eosinophilic, and the red lineage and megakaryocytes were normal. Under the electron microscope, the primitive cells often had a lymphocyte-like appearance, with rounded and depressed or irregular nuclei, medium density of chromatin, obvious nucleoli, high nuclear/cytoplasmic ratios, mitochondria in the cytoplasm, and rare rough endoplasmic reticulum, Golgi apparatus, and a large number of glycogen aggregates. Primitive cells contain three types of granules: ① immature basophilic granules, which provide basophilic differentiation of primitive cells and often show peroxidase positivity. ② Theta granules, which may be associated with early basophilic differentiation, are often peroxidase negative. (iii) Immature mast cell granules, which provide evidence of mast cell differentiation, rare primitive cells characterized by both basophilic and mast cell differentiation, and often negative for peroxidase.