D-dimer
Biochemistry
| Synonym | Cross-linked fibrin degradation products |
|---|---|
| Molecular mass | 195.000 Da D-Dimer 247.000 Da D-Dimer-E-Fragment |
Cross-linking of soluble fibrin to the insoluble fibrin is the last step in plasmatic coagulation. Fibrinolysis as the counter reaction has the task of lysing the fibrin clot. Plasmin is the central enzyme in this process and cleaves the fibrin clot at specific sites. This process takes place in several steps via high molecular fragments and soluble aggregates down to the D-dimer and D-dimer-E fragments, which cannot be any further degraded by plasmin. The determination of D-dimer allows a direct determination of plasmin activity.
Clinical significance
Elevated concentrations of D-dimer can be observed in a variety of diseases and during fibrinolytic therapy (e.g. with streptokinase and t-PA). In all diseases with an elevated activation (e.g. thromboembolism and DIC) hyperfibrinolysis has been observed as the counter reaction to the elevated fibrin formation. D-dimer is a marker for this hyperfibrinolysis. Elevated D-dimer concentrations thus can be observed in thromboembolic diseases (pulmonary embolism, deep venous thrombosis), leukaemia and sepsis, intra- and postoperative, in physical and mental stress and during extra corporeal circulation.
Indication
- Monitoring of hyperfibrinolysis in DIC
- Suspected hyperfibrinolysis as the cause of a haemorrhagic diathesis
- Complications in pregnancy: diagnosis of a severe preeclampsia
- Exclusion diagnosis in suspected venous thrombosis and pulmonary embolism with negative test results and/or a stronger suspicion with positive results.
Literature
- Olson JD. D-dimer: An Overview of Hemostasis and Fibrinolysis, Assays, and Clinical Applications. Adv Clin Chem. 69, 1-46, 2015.
- Halaby R, Popma CJ, Cohen A, Chi G, Zacarkim MR, Romero G, Goldhaber SZ, Hull R, Hernandez A, Mentz R, Harrington R, Lip G, Peacock F, Welker J, Martin-Loeches I, Daaboul Y, Korjian S, Gibson CM. D-Dimer elevation and adverse outcomes. J Thromb Thrombolysis. Jan 39(1), 55-9, 2015.
- Tripodi A. D-dimer testing in laboratory practice. Clin Chem. 2011 Sep;57(9):1256-62. doi: 10.1373/clinchem.2011.166249. Epub Jun 30 2011.
- Linkins LA, Takach Lapner S. Review of D-dimer testing: Good, Bad, and Ugly. Int J Lab Hematol. May 39 Suppl 1:98-103. 2017.
- Pulivarthi S Gurram K Effectiveness of D-Dimer as a Screening Test for Venous Thromboembolism: An Update N Am J Med Sci. 2014 Oct; 6(10): 491–499.