What Does an Elevated D-Dimer Level Mean?

Elevated D-dimer levels often indicate secondary fibrinolysis in the human body. Common conditions include deep vein thrombosis and pulmonary artery thrombosis. As a large number of thrombi form in the body, the fibrinolytic system is activated, leading to a significant increase in D-dimer levels. D-dimer is one of the degradation products of cross-linked fibrin in the human body and a unique metabolite of secondary fibrinolysis hyperfunction. In a normal human body, the content of D-dimer is 0-200μg/L, and the qualitative test is negative.

Significantly elevated D-dimer levels are a necessary condition for the diagnosis of deep vein thrombosis and pulmonary embolism. Additionally, when various diseases cause disseminated intravascular coagulation, D-dimer levels also increase significantly. Simultaneously, during thrombolytic treatment for thrombotic diseases, D-dimer levels may also increase significantly.

Elevated D-dimer levels are indicative of thrombosis. In cases of significant elevation, it is generally recommended to repeat venous ultrasonography of the lower limbs. This is because sometimes after venous thrombosis, the process of self-dissolution in the body can lead to an increase in D-dimer levels. If elevated D-dimer levels are detected, it suggests that the patient may have venous thrombosis somewhere in the body. Therefore, it is necessary to check if venous thrombosis has occurred in the legs, as this is the area most susceptible to venous thrombosis.

Moreover, some venous thromboses, especially in the calves, may not be apparent with mild swelling, and are undetectable by visual inspection. Therefore, ultrasonography is a simple and highly accurate method for diagnosis. If the patient also experiences symptoms such as dyspnea, suffocation, or chest pain, it is recommended to perform a CT scan of the pulmonary arteries to exclude the possibility of pulmonary embolism. Pulmonary embolism poses a higher risk and harm than lower extremity venous thrombosis, and stricter treatment measures are often necessary once it occurs.