The role of D-Dimer in clinical practice

Post by Master, Doctor Phan Van Phong - Emergency Doctor - Emergency Department - Vinmec Central Park International General Hospital

The role of the d-dimer is to diagnose venous thromboembolic diseases, the risk of arterial and venous thrombosis, and to determine the optimal duration of secondary prevention for patients after an thromboembolic event. Venous thromboembolism as well as diagnosis and monitoring of disseminated intravascular coagulation.

D-dimer is a breakdown product of fibrin. The formation of D-Dimer involves three important enzymes:
Thrombin: Formed by activation of the coagulation cascade. Thrombin converts fibrinogen into fibrin clots. Activated factor XIII creates cross-links in the fibrin clot through covalent bridges between fibrin monomers. Plasmin: Is an enzyme of the fibrinolytic process that destroys fibrin clots.

D-Dimer detection test using monoclonal antibodies. These monoclonal antibodies are specific for the epitopes on the D-Dimer fragment but do not bind to the epitopes on fibrin, fibrinogen, or other non-crosslinked fibrin fragments, so this monoclonal antibody is specific for D-Dimer.
Types of D-Dimer tests:
Elisa test: Quantitative, highly sensitive but time consuming Manual Latex Immunoassay: Semi-quantitative and less sensitive than Elisa but faster. Latex-linked immunoassay has all the advantages of the Elisa method but is very fast and can be integrated on conventional coagulation machines.

D-dimer has a half-life of 8h. D-dimer can be detected about 2 h after clot formation. D-dimer is not a specific marker of coagulation activity because of the overlap between coagulation and inflammation. Increased D-dimer can be seen in cases of fibrin formation and degradation other than coagulation such as: surgery, cardiac arrhythmia, pregnancy, trauma, infection, myocardial infarction.

D dimer value used as a diagnostic threshold is: 500 mcg/L People over 50 years old: age X 10 (mcg/L)

D-dimer has a role in the diagnosis of the following diseases:
Diagnosis of venous thromboembolism Detecting patients at risk of developing arterial and venous thrombosis The role of d-dimer in risk detection VTE risk of recurrence Determine optimal duration of secondary prevention for patients after a VTE event Monitor risk of gestational thrombosis Diagnose/monitor disseminated intravascular coagulation Precautions when using D-Dimer in the diagnosis of venous thromboembolism (VTE) in patients with the following factors:
Have had symptoms of VTE more than 14 days ago Have decreased fibrinolysis Suspicion suspected VTE being treated with Heparin or oral anticoagulants Having recurrent VTE Elderly Patients with long hospital stays In summary, D-dimer is a breakdown product of fibrin clots. D-dimer has a role in the diagnosis of VTE, the risk of arterial and venous thrombosis, and determining the optimal duration of secondary prevention for patients after a thromboembolic event. venous thrombosis, monitoring of gestational thromboembolism risk, as well as diagnosis and monitoring of disseminated intravascular coagulation.