In clinical work, it has been found that diseases such as connective tissue disease, hypersplenism, and megaloblastic anemia can also manifest as peripheral thrombocytopenia and impaired maturation of bone marrow megakaryocytes. Blood test items for bone marrow megakaryocyte maturation disorder: 1. Blood routine shows only thrombocytopenia while all other lineages are in normal range. The reticulocyte count of ITP alone is basically normal. 2. Peripheral blood smear Pseudo-thrombocytopenia due to ethylenediaminetetraacetic acid (EDTA)-dependent platelet coagulation should be excluded. The presence of broken red blood cells should exclude thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome. The presence of giant platelets or microplatelets should be considered hereditary thrombocytopenia. Bone marrow smear The bone marrow is actively proliferating, and megakaryocytes are generally significantly increased and sometimes normal. The more prominent changes are imbalance in the nucleoplasmic maturation of megakaryocytes, less granules in the cytoplasm, and a significant decrease or lack of platelet-producing megakaryocytes. 4, HIV (HIV) and hepatitis C virus (HCV) testing HIV and HCV testing should be performed in adult patients considering ITP. Thrombocytopenia caused by HIV and HCV infection is sometimes difficult to distinguish clinically from patients with primary ITP. 5.Immunoglobulin quantification More measurement of serum IGG, IgA, IGM levels. Low levels of immunoglobulins often suggest variant immunodeficiency disease or selective IgA deficiency.