High d-dimer refers to high D-dimer, which is considered to be related to disseminated intravascular coagulation, deep vein thrombosis, acute myocardial infarction, burns and so on. 1. Disseminated intravascular coagulation: the disease is related to severe infection, malignant tumor, medication, surgery, etc., which can cause high D-dimer due to coagulation activation and large consumption of coagulation factors. Common manifestations of patients include bleeding, shock, microthrombosis, etc. 2. Deep vein thrombosis: the disease is related to the damage of vein wall, stagnation of venous blood flow and hypercoagulable state of blood, and high D-dimer can be seen in medical examination. The main symptoms of patients include swelling and pain of lower limbs, skin color change, etc. 3. Acute myocardial infarction: the disease is related to the decrease of blood perfusion in the heart, insufficient oxygen supply to the heart muscle, increased oxygen consumption of the heart muscle, etc., and high D-dimer can be seen due to the lack of blood supply to the heart. Common symptoms include weakness, pain or stuffiness in the precordial area, palpitations (rapid heartbeat, often accompanied by panic), shortness of breath, and so on. 4. Burns: Some burn patients may have high D-dimer due to the reduction of total blood volume, high metabolic state, increased fibrinolytic activity, etc. Usually, patients will have erythema of the skin. Usually, the patient’s skin will appear erythema, blisters or yellowish skin and other conditions. There are many causes of high D-dimer, such as cerebral infarction, pulmonary embolism, malignant tumor, liver disease, septicemia and so on. Patients are advised to do further detailed examination in order to clarify the cause of the disease and then follow the doctor’s instructions for treatment.