Impaired megakaryocyte maturation is often considered a typical change in the bone marrow examination of idiopathic thrombocytopenic purpura (ITP). In clinical work, it is found that diseases such as connective tissue disease, hypersplenism, and megaloblastic anemia can also manifest as peripheral thrombocytopenia and impaired bone marrow megakaryocyte maturation. Examination and diagnosis of bone marrow megakaryocyte maturation disorders: 1. Histopathological examination It can be used as a diagnostic aid and is non-specific. The typical pathology is a homogeneous “hyaline” platelet thrombus in small arteries and capillaries with positive PAS staining and vWF factor and very low fibrin/fibrinogen content. In addition, there is endothelial hyperplasia, subendothelial “hyaline-like” material deposition, periarterial concentric fibrosis, etc. There may be local necrosis in the embolus, and generally no inflammatory reaction. At present, it is rarely used, except to find the primary disease. 2.Coagulogram examination should be sought to assist in the diagnosis if possible. PT and fibrinogen are basically normal in this disease. D-dimer, fibrin degradation products, thrombin-antithrombin complex, fibrinogen activator inhibitor (PAI-1), thrombomodulin, etc. may be mildly increased. 3. Other elevated vWF factors in plasma, anti-platelet antibodies, anti-CD36 antibodies, UL-vWF, etc. may be found, and liver transaminases may also be increased. Bacteriological examination of E. coli should be performed if HUS is suspected.