If the examination reveals that D-dimer is more than 4 points i.e. greater than 4mg/L, it indicates that it is higher than the normal value, which may or may not be serious. Because of the low specificity and high sensitivity of this index, the changes of its measurement value are also used clinically to judge the effect of thrombolytic therapy, so a comprehensive analysis is needed.1. Not serious: When bleeding with clot formation occurs, the D-dimer detection value can also be increased to more than 4mg/L, such as when coagulation occurs in traumatic wounds, which is normal at this time. And during the thrombolytic treatment, the D-dimer test value cannot fall off a cliff to the normal level. If the test is performed during the treatment and the result value is lower than the previous test value, it usually indicates that the treatment is effective, not a serious situation, and belongs to the normal reaction; 2. Serious: If there is no the above situation, and the simple examination finds that the D-dimer test value is greater than 4mg/L, it is a serious situation, suggesting that Aortic coarctation, diffuse intravascular coagulation, lung cancer, acute promyelocytic leukemia, pulmonary thromboembolism, deep vein thrombosis, etc. may occur in the body. These diseases can seriously threaten the life and health of patients and therefore require vigilance. Patients are advised to improve relevant examinations in time to understand the specific causes, and can use anticoagulants or thrombolytic drugs for improvement. Generally, patients can recover with active, standardized and persistent treatment.