Platelets are low in routine blood tests, while others are normal. Causes include taking certain medications, hematologic diseases, immune disorders, cirrhosis of the liver, and so on. Further examination is needed to find out the cause of the disease and target treatment. 1. Taking certain drugs: such as chloramphenicol, sulfonamides, aspirin drugs, etc. Generally, the symptoms of thrombocytopenia can be improved by stopping the use of such drugs. 2. Hematologic disorders: such as insufficient platelet production by the bone marrow, certain bone marrow disorders, such as myelodysplastic syndromes, which can be diagnosed by bone marrow aspiration. 3. Immune diseases: for example, idiopathic thrombocytopenic purpura is due to the production of antiplatelet antibodies in the body, which are destroyed by the spleen when combining with platelets, resulting in the shortening of platelet lifespan, and therefore thrombocytopenia can be seen in routine blood tests. 4. Cirrhosis: patients with cirrhosis, due to hypersplenism, platelet destruction increases, so the symptoms of thrombocytopenia, you can check the liver function, liver, gallbladder, pancreas and spleen ultrasound to confirm the diagnosis. Blood test, if the platelet is slightly reduced, can carry out regular review of blood routine, if the thrombocytopenia is serious, need to be timely under the guidance of the physician therapeutic intervention, so as not to delay the condition.