Medical expert of the article
New publications
D dimer
Last reviewed: 06.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
When fibrin fibers are split, fragments called D-dimers are formed. When determining the content of D-dimers using specific antisera, it is possible to judge the degree to which fibrinolysis, but not fibrogenolysis, is expressed in the blood being examined.
Reference values (norm) for D-dimer concentration in blood plasma are less than 0.25 μg/ml (250 μg/l) or 0.5 μg fibrinogen equivalents/ml (500 μg fibrinogen equivalents/l).
Determination of D-dimer in plasma is used to exclude thrombosis of any localization and to diagnose DIC syndrome. In pulmonary embolism, the D-dimer content in plasma usually exceeds 0.5 μg/ml (500 μg/l).
[ Who to contact?
Causes of increased D-dimer
Increased D-dimer content is one of the main markers of hemostasis system activation, since it reflects both fibrin formation in the blood being tested and its lysis. The period of D-dimer elimination from the bloodstream is 6 hours, which is significantly higher than other markers of coagulation cascade activation (fragment 1+2 - a product of prothrombin proteolysis, thrombin-antithrombin complex, fibrinopeptide A). In this regard, blood plasma samples cannot be stored for more than 6 hours.
Increased concentrations of D-dimer in blood plasma may occur in cases of coronary heart disease, myocardial infarction, malignant tumors, liver diseases, active inflammatory processes, infectious diseases, extensive hematomas, thrombolytic therapy, pregnancy, and in individuals over 80 years of age.
The introduction of heparin causes a sharp and immediate drop in the concentration of D-dimer in the plasma, which continues more slowly in the future during treatment with direct anticoagulants. The administration of indirect anticoagulants is also accompanied by a decrease in the content of D-dimer, but it is more gradual. Usually, during treatment with indirect anticoagulants, the concentration of D-dimer below 500 μg/l is achieved after 3 months.
In patients with tissue plasminogen activator deficiency or high plasminogen activator inhibitor activity (which leads to a decrease in the fibrinolytic activity of blood plasma), the concentration of D-dimer may not increase even in the presence of deep vein thrombosis or pulmonary embolism.
In patients with myocardial infarction and obliterating atherosclerosis of the lower extremity vessels, an increased concentration of D-dimer in the blood plasma is associated with an increased likelihood of complications. An increase in the level of D-dimer and fibrinogen in patients with a permanent form of atrial fibrillation is considered a harbinger of thromboembolic complications.
Infections, inflammatory processes, hemorrhagic complications, the presence of rheumatoid factor in the blood, and the formation of fibrin during the healing of postoperative wounds may be accompanied by an increase in the concentration of D-dimer.
The diagnostic sensitivity of D-dimer determination for the diagnosis of pulmonary embolism is 90%, specificity is less than 50%, for the diagnosis of deep vein thrombosis - 60-100% and 29-91%, respectively.
The concentration of D-dimer in blood plasma increases in the early stages of pregnancy, reaching values 3-4 times higher than the initial ones by the end of pregnancy. Significantly higher concentrations of D-dimer are detected in women with pregnancy complications (gestosis, preeclampsia), as well as in pregnant women with diabetes and kidney diseases.