D-dimer: Difference between revisions

Latest revision as of 03:52, 13 February 2025

D-dimer[edit]

D-dimer is a fibrin degradation product (or FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is named because it contains two D fragments of the fibrin protein joined by a cross-link. D-dimer concentration may be determined by a blood test to help diagnose thrombosis.

Clinical significance[edit]

D-dimer is a significant marker in the diagnosis of thrombotic disorders. It is used primarily to exclude the presence of an inappropriate blood clot (thrombus). A negative D-dimer test indicates that it is highly unlikely that a thrombus is present. Conversely, a positive D-dimer test is not specific and does not confirm the presence of a thrombus, as D-dimer levels can be elevated in other conditions such as inflammation, infection, or liver disease.

Diagnostic use[edit]

The D-dimer test is commonly used in the diagnosis of deep vein thrombosis (DVT), pulmonary embolism (PE), and disseminated intravascular coagulation (DIC). It is particularly useful in emergency settings to rule out thromboembolic events in patients with low to moderate risk.

Pathophysiology[edit]

D-dimer is formed by the action of plasmin on cross-linked fibrin. When a blood clot is formed, the coagulation cascade is activated, leading to the conversion of fibrinogen to fibrin. Fibrin forms a mesh that stabilizes the clot. Plasmin, an enzyme, breaks down the fibrin mesh, resulting in the release of D-dimer into the bloodstream.

Testing[edit]

D-dimer levels are measured using a blood test. The test is often performed using an enzyme-linked immunosorbent assay (ELISA) or a latex agglutination test. The results are typically reported in fibrinogen equivalent units (FEU) or D-dimer units (DDU).

Limitations[edit]

While the D-dimer test is a useful tool for ruling out thrombotic events, it has limitations. Elevated D-dimer levels can occur in a variety of conditions, including pregnancy, trauma, surgery, and cancer. Therefore, a positive D-dimer test must be interpreted in the context of the patient's clinical presentation and risk factors.

Related pages[edit]

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-'''D-dimer''' is a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is named so because it contains two D fragments of the fibrin protein joined by a cross-link.
+== D-dimer ==
-== Overview ==
+[[File:D-dimer.png|thumb|right|200px|Structure of D-dimer]]
-D-dimer concentration may be determined by a blood test to help diagnose thrombosis. Since its introduction in the 1990s, it has become an important test performed in patients with suspected thrombotic disorders. While a negative result practically rules out thrombosis, a positive result can indicate thrombosis but does not rule out other potential causes. Its main use, therefore, is to exclude thromboembolic disease where the probability is low.
-== Clinical Use ==
+'''D-dimer''' is a fibrin degradation product (or FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is named because it contains two D fragments of the fibrin protein joined by a cross-link. D-dimer concentration may be determined by a blood test to help diagnose thrombosis.
-In patients suspected of disseminated intravascular coagulation (DIC), D-dimer is a useful test. If DIC is suspected, D-dimer levels will be very high. In patients with suspected pulmonary embolism (PE) or deep vein thrombosis (DVT), D-dimer testing has been shown to be sensitive but not specific. In other words, a negative D-dimer is useful for ruling out PE or DVT, but a positive D-dimer does not confirm either diagnosis.
-== Interpretation ==
+== Clinical significance ==
-D-dimer is elevated in any condition in which fibrin is formed and then broken down. Therefore, its concentration increases in conditions such as deep vein thrombosis, pulmonary embolism, myocardial infarction, and infection. However, it is also often elevated in pregnancy, surgery, trauma, and cancer, limiting its specificity.
-== See Also ==
+D-dimer is a significant marker in the diagnosis of [[thrombotic disorders]]. It is used primarily to exclude the presence of an inappropriate blood clot (thrombus). A negative D-dimer test indicates that it is highly unlikely that a thrombus is present. Conversely, a positive D-dimer test is not specific and does not confirm the presence of a thrombus, as D-dimer levels can be elevated in other conditions such as [[inflammation]], [[infection]], or [[liver disease]].
+=== Diagnostic use ===
+The D-dimer test is commonly used in the diagnosis of [[deep vein thrombosis]] (DVT), [[pulmonary embolism]] (PE), and [[disseminated intravascular coagulation]] (DIC). It is particularly useful in emergency settings to rule out thromboembolic events in patients with low to moderate risk.
+== Pathophysiology ==
+D-dimer is formed by the action of [[plasmin]] on cross-linked fibrin. When a blood clot is formed, the coagulation cascade is activated, leading to the conversion of fibrinogen to fibrin. Fibrin forms a mesh that stabilizes the clot. Plasmin, an enzyme, breaks down the fibrin mesh, resulting in the release of D-dimer into the bloodstream.
+== Testing ==
+D-dimer levels are measured using a blood test. The test is often performed using an enzyme-linked immunosorbent assay (ELISA) or a latex agglutination test. The results are typically reported in fibrinogen equivalent units (FEU) or D-dimer units (DDU).
+== Limitations ==
+While the D-dimer test is a useful tool for ruling out thrombotic events, it has limitations. Elevated D-dimer levels can occur in a variety of conditions, including [[pregnancy]], [[trauma]], [[surgery]], and [[cancer]]. Therefore, a positive D-dimer test must be interpreted in the context of the patient's clinical presentation and risk factors.
+== Related pages ==
+* [[Thrombosis]]
+* [[Fibrinolysis]]
+* [[Coagulation]]
+* [[Pulmonary embolism]]
 * [[Deep vein thrombosis]]
-* [[Pulmonary embolism]]
-* [[Myocardial infarction]]
-* [[Disseminated intravascular coagulation]]
-== References ==
-<references />
+[[Category:Hematology]]
 [[Category:Medical tests]]
-[[Category:Coagulation system]]
-[[Category:Blood tests]]
-{{stub}}