- What is D-dimer
- D-dimer test
- How is D-dimer test used?
- When is D-dimer test ordered?
- D-dimer levels
- High D-dimer levels
- What other procedures might my healthcare practitioner order if my D-dimer is positive?
- D-dimer test
D-dimer is one of the protein fragments produced when a blood clot gets dissolved in the body (see Figure 1B below – Fibrinolytic Pathway). D-dimer is normally undetectable or detectable at a very low level unless your body is forming and breaking down blood clots. Then, D-dimer level in your blood can significantly rise.
When a blood vessel or tissue is injured and begins to bleed, a process called hemostasis is initiated by the body to create a blood clot to limit and eventually stop the bleeding. This process produces threads of a protein called fibrin, which crosslink together to form a fibrin net. That net, together with platelets, helps hold the forming blood clot in place at the site of the injury until it heals.
Once the area has had time to heal and the clot is no longer needed, the body uses an enzyme called plasmin to break the clot (thrombus) into small pieces so that it can be removed. The fragments of the disintegrating fibrin in the clot are called fibrin degradation products (FDP), which consist of variously sized pieces of crosslinked fibrin. One of the final fibrin degradation products produced is D-dimer, which can be measured in a blood sample when present. The level of D-dimer in the blood can significantly rise when there is significant formation and breakdown of fibrin clots in the body.
For a person who is at low or intermediate risk for blood clotting (thrombosis) and/or thrombotic embolism, the strength of the D-dimer test is that it can be used in a hospital emergency room setting to determine the likelihood of a blood clot’s presence. A negative D-dimer test (D-dimer level is below a predetermined cut-off threshold) indicates that it is highly unlikely that a thrombus is present. However, a positive D-dimer test cannot predict whether or not a blood clot is present. However, a positive D-dimer test does not tell your doctor where the blood clot was or what caused it.Other health problems can also cause the D-dimer level to go up (see High D-dimer levels below for causes). Therefore, the D-dimer test is not the only test used to diagnose a disease or condition. D-dimer test is usually used with other blood tests and imaging scans. Positive D-dimer test indicates that further diagnostic procedures are required (e.g., ultrasound, CT angiography).
There are several factors and conditions associated with inappropriate blood clot formation. One of the most common is deep vein thrombosis (DVT), which involves clot formation in veins deep within the body, most frequently in the lower legs. These clots may grow very large and block blood flow in the legs, causing swelling, pain, and tissue damage. It is possible for a piece of the clot to break off and travel to other parts of the body. This “embolus” can lodge in the lungs, causing a pulmonary embolus or embolism (PE). Pulmonary embolisms from deep vein thrombosis (DVT) affect more than 300,000 people in the U.S. each year.
While blood clots most commonly form in the veins of the legs, they may also form in other areas as well. Measurements of D-dimer can be used to help detect clots in any of these sites. For example, clots in coronary arteries are the cause of myocardial infarction (heart attacks). Clots may form on the lining of the heart or its valves, particularly when the heart is beating irregularly (atrial fibrillation) or when the valves are damaged. Clots can also form in large arteries as a result of narrowing and damage from atherosclerosis. Pieces of such clots may break off and cause an embolus that blocks an artery in another organ, such as the brain (causing a stroke) or the kidneys.
Measurements of D-dimer may also be ordered, along with other tests, to help diagnose disseminated intravascular coagulation (DIC). Disseminated intravascular coagulopathy (DIC) is a condition in which clotting factors are activated and then used up throughout the body. This creates numerous tiny blood clots and at the same time leaves the affected person vulnerable to excessive bleeding. It is a complex, sometimes life-threatening condition that can arise from a variety of situations, including some surgical procedures, sepsis, poisonous snake bites, liver disease, and after childbirth. Steps are taken to support the affected person while the underlying condition resolves. The D-dimer level will typically be very elevated in disseminated intravascular coagulopathy (DIC).
Figure 1. Overview of blood coagulation
D-dimer test measures the amount of D-dimer, which is normally undetectable, in your blood. A D-dimer test is a blood test usually used to help check for or monitor blood clotting problems. A positive test means the D-dimer level in your body is higher than normal and suggests you might have blood clots.
Blood clots form whenever a blood vessel is damaged, whether that’s by an injury or by atherosclerosis, or when blood flow is restricted, such as by a vessel being compressed for a long time. When you have an injury, your body creates a blot clot to stop blood from leaking out of your blood vessels. D-dimer is a type of protein your body produces to break down the blood clot.
D-dimer testing is not well studied in children.
How is D-dimer test used?
D-dimer tests are used to help rule out the presence of an inappropriate blood clot (thrombus). Your doctor might ask you to have D-dimer test if he or she suspects you have blood clotting problems or wants to rule them out.
Some of the conditions that the D-dimer test is used to help rule out include:
- Deep vein thrombosis (DVT) — clot formation in the veins, usually in the legs
- Pulmonary embolism (PE) — a blockage in an artery in the lung
- Disseminated intravascular coagulation (DIC) — a condition that prevents your blood clotting normally.
- Blood coagulation caused by venom of certain species of snake, such as brown snake.
D-dimer test may be used to determine if further testing is necessary to help diagnose diseases and conditions that cause hypercoagulability, a tendency to clot inappropriately.
A D-dimer level may be used to help diagnose disseminated intravascular coagulation (DIC) and to monitor the effectiveness of disseminated intravascular coagulation (DIC) treatment.
When is D-dimer test ordered?
D-dimer testing is often ordered when someone goes to the emergency room with symptoms of a serious condition (e.g., chest pain and difficulty in breathing).
A D-dimer test may be ordered when someone has symptoms of deep vein thrombosis (DVT), such as:
- Leg pain or tenderness, usually in one leg
- Leg swelling, edema
- Discoloration of the leg
D-dimer test may be ordered when someone has symptoms of pulmonary embolism (PE) such as:
- Sudden shortness of breath, labored breathing
- Coughing, hemoptysis (blood present in sputum)
- Lung-related chest pain
- Rapid heart rate
D-dimer is especially useful when a healthcare practitioner thinks that something other than deep vein thrombosis or pulmonary embolism is causing the symptoms. It is a quick, non-invasive way to help rule out abnormal or excess clotting as the underlying cause. However, it should not be used when the probability of pulmonary embolism is high based on clinical assessment.
When a person has symptoms of disseminated intravascular coagulation (DIC), such as bleeding gums, nausea, vomiting, severe muscle and abdominal pain, seizures, and decreased urine output, a D-dimer test may be ordered, along with a prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet count, to help diagnose the condition. D-dimer may also be ordered at intervals when someone is undergoing treatment for disseminated intravascular coagulation (DIC) to help monitor its progress.
There are several different methods of testing for D-dimer. The currently available D-dimer tests that yield quantitative results are typically done in a hospital lab. Since different tests are used in different units, the results of one cannot be extrapolated to another.
- Less than or =250 ng/ml D-Dimer Units (DDU)
- Less than or =500 ng/mL (< or =0.50 mcg/mL) Fibrinogen Equivalent Units (FEU)
D-dimer values < or =250 ng/mL D-Dimer Units (DDU) (< or =0.50 mcg/mL Fibrinogen Equivalent Units [FEU]) are normal. Within the reportable normal range (110-250 ng/mL DDU; 0.22-0.50 mcg/mL FEU), measured values may reflect the activation state of the procoagulant and fibrinolytic systems, but the clinical utility of such quantitation is not established.
A normal D-dimer result (< or =250 ng/mL D-Dimer Units (DDU); < or =0.50 mcg/mL Fibrinogen Equivalent Units [FEU]) has a negative predictive value of approximately 95% for the exclusion of acute pulmonary embolism (PE) or deep vein thrombosis (DVT) when there is low or moderate pretest pulmonary embolism or deep vein thrombosis probability. In other words, a normal or “negative” D-dimer result (< or =250 ng/mL D-Dimer Units (DDU); < or =0.50 mcg/mL Fibrinogen Equivalent Units [FEU]) means that it is most likely that the person tested does not have an acute condition or disease causing abnormal clot formation and breakdown. Most health practitioners agree that a negative D-dimer is most valid and useful when the test is done for people who are considered to be at low to moderate risk for thrombosis. TheD-dimer test is used to help rule out clotting as the cause of symptoms.
D-dimer concentrations increase with age and, thus, the specificity for deep vein thrombosis (DVT) and pulmonary embolism (PE) exclusion decreases with age. For deep vein thrombosis (DVT) or pulmonary embolism (PE) exclusion, in addition to clinical pretest probability, age-adjusted D-dimer cutoffs are suggested for patients more than 50 years of age.
Recent evidence suggests using clinical pretest probability and age-adjusted cutoffs to improve the performance of D-dimer testing in patients greater than 50 years of age. In recent studies, when compared to a fixed D-dimer cutoff, age adjusted D-dimer cutoff values (calculated as follows: age [years] x 10 ng/mL) resulted in equivalent outcomes and no additional false negative findings 1).
Lipemia can interfere with this assay, occasionally causing an under-estimation of the D-dimer level. Therefore, results from lipemic specimens should be interpreted with caution.
High D-dimer levels
Elevated D-dimer values are abnormal but do not indicate a specific disease state.A higher than normal D-dimer level might mean you have had a significant blood clot. A positive D-dimer result may indicate the presence of an abnormally high level of fibrin degradation products. Elevated D-dimer value indicates that there may be significant blood clot (thrombus) formation and breakdown in the body, but it does not tell the location ofthe clot or what caused it. For example, it may be due to a venous thromboembolism (VTE) or disseminated intravascular coagulation (DIC). Typically, the D-dimer level is very elevated in disseminated intravascular coagulation (DIC).
However, an elevated D-dimer does not always indicate the presence of a clot because a number of other factors can cause an increased level. Elevated D-dimer levels may be seen in conditions in which fibrin is formed and then broken down, such as recent surgery, trauma, infection, heart attack, and some cancers or conditions in which fibrin is not cleared normally, such as liver disease. Therefore, D-dimer is typically not used to rule out venous thromboembolism (VTE) in hospitalized patients (inpatient setting).
Fibrin is also formed and broken down during pregnancy, so that may result in an elevated D-dimer level. However, if disseminated intravascular coagulation (DIC) is suspected in a woman who is pregnant or is in the immediate postpartum period, then the D-dimer test may be used, along with a prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, and platelet count to help diagnose her condition. If the woman has disseminated intravascular coagulation (DIC), her D-dimer level will be very elevated.
D-dimer is recommended as an adjunct test. Since D-dimer is a sensitive test but has a poor specificity, it should only be used to rule out deep vein thrombosis (DVT), not to confirm a diagnosis. D-dimer test should not be used for pulmonary embolism when the clinical probability of that condition is high. Both increased and normal D-dimer levels may require follow-up and can lead to further diagnostic testing. People with positive D-dimer tests and those with moderate to high risk for DVT require further study with diagnostic imaging (e.g., CT angiography).
When used to monitor DIC treatment, decreasing levels indicate that treatment is effective while increasing levels may indicate that treatment is not working.
D-dimer values may be elevated as a result of:
- Clinical or subclinical disseminated intravascular coagulopathy (DIC) or intravascular coagulation and fibrinolysis.
- Other conditions associated with increased activation of the procoagulant and fibrinolytic mechanisms such as:
- Recent surgery,
- Active or recent bleeding,
- D-dimer levels can be positive due to:
- Liver disease,
- Hypercoagulable (procoagulant) states,
- High lipid or triglyceride levels (lipidemia)
- Heart disease
- Being over 80 years old
Other health problems outlined above can also cause the D-dimer level to go up. This makes the D-dimer test mostly useful when it is negative, when many of the above causes can be ruled out.
Therefore, the D-dimer test is not the only test used to diagnose a disease or condition. It is usually used with other blood tests and imaging scans. And the degree of D-dimer increase does not definitely correlate with the clinical severity of associated disease states.
Common risk factors for inappropriate blood clotting
Some risk factors include:
- Major surgery or trauma
- Hospitalization or living in a nursing home
- Prolonged immobility—this can include long trips by plane, car, etc. or prolonged bed rest
- Use of birth control or hormone replacement therapy
- Broken bone, cast
- Pregnancy or recent childbirth
- Antiphospholipid syndrome
- Certain cancers
- Inherited clotting disorder such as factor V Leiden mutation
- History of prior venous thromboembolism (VTE)
If the D-dimer test is positive, then you might be sent for imaging. A normal D-dimer level usually indicates a clotting problem is unlikely.
The presence of rheumatoid factor(a protein seen in people with rheumatoid arthritis) at a level above 50 IU/mL may lead to an overestimation of the D-dimer level.
What other procedures might my healthcare practitioner order if my D-dimer is positive?
In an emergency room setting, if you are found to be at low to intermediate risk for thrombosis and/or venous thromboembolism and when you have a positive D-dimer test, your healthcare practitioner will likely order a non-invasive scanning procedure, such as a venous ultrasound, multi-detector helical computed axial tomography (CT), direct pulmonary angiography, or ventilation-perfusion (V/Q) scan.
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Also, high D-dimer levels are not always caused by clotting problems. Other conditions that can cause high D-dimer levels include pregnancy, heart disease, and recent surgery. If your D-dimer results were not normal, your provider will probably order more tests to make a diagnosis.What can cause falsely elevated D-dimer? ›
 Of note, there are several physiologic states or medical conditions that may cause patients to have an elevated D-dimer in the absence of PE, DVT, or DIC. These include but are not limited to pregnancy, malignancy, cigarette smoking, trauma, or infection, or sepsis.Can D-dimer be high without clots? ›
It's possible to have high D-dimer levels without having a blood clotting condition. Other conditions and situations that can cause higher-than-normal levels of D-dimer include: Pregnancy. Heart disease.Can D-dimer tests be wrong? ›
A D-dimer with high sensitivity (eg ELISA) will miss few patients who have VTE, but due to low specificity, it will also produce a large number of false-positive results. False-positive D-dimer results lead to unnecessary ultrasounds and CT scans.What type of inflammation causes high D-dimer? ›
Vasculitis seems to be a common pathophysiologic link between the other reports of inflammatory conditions and elevated D-dimer levels. These reports include Henoch-Schönlein purpura, Kawasaki disease, eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), and Behçet syndrome.What does an elevated D-dimer indicate? ›
One of those leftovers is called D-dimer. It's part of a protein. Normally, with a little time, it goes away. But you can get high levels of D-dimer in your blood if you have a major clot like with deep vein thrombosis (DVT).How accurate are D-dimer tests? ›
The sensitivity of D-dimer was 86% and 83% in patients with and without cancer, respectively.Can inflammation cause elevated D-dimer? ›
Elevated levels of d-dimer are associated with inflammation and disease activity rather than risk of venous thromboembolism in patients with granulomatosis with polyangiitis in long term observation. Adv Med Sci. 2020 Mar;65(1):97-101.What medications cause elevated D-dimer? ›
Both antiplatelet drugs and HMG‐CoA reductase inhibitors (statins) have been associated with effects on thrombus formation, potentially influencing D‐dimer levels in this setting, leading to a higher rate of false‐negative tests.What are the first signs of a blood clot? ›
Symptoms of a blood clot include: throbbing or cramping pain, swelling, redness and warmth in a leg or arm. sudden breathlessness, sharp chest pain (may be worse when you breathe in) and a cough or coughing up blood.
Statins have proven antithrombotic properties, as suggested by the reduction of several prothrombotic markers, including D-dimer, in patients at high risk of arterial thrombosis. Such antithrombotic properties could also be observed in patients at high risk of venous thrombosis.What cancers cause elevated D-dimer? ›
The plasma levels of D-dimer were significantly higher in patients with breast cancer (P=0.0022), gastric cancer (P<0.0001), pancreatic cancer (P=0.0003), colon cancer (P=0.0001) and rectal cancer (P=0.0028), compared with the healthy controls.How long does it take for D-dimer to normalize? ›
In our experience, we observed that after complete clinical recovery from COVID-19, restoration of wellbeing, and normalization of molecular swab, 20% of patients had substantially elevated levels of D-dimer, which returned progressively to normal after about two weeks of treatment with prophylactic doses of enoxaparin ...What autoimmune diseases cause high D-dimer? ›
The increased D-dimer has been reported in conditions with thrombosis (16), IBD (17, 23), rheumatoid arthritis (RA) (24, 25), and SpA (20), while FIB increases under injury, infection, or inflammation.Does elevated D-dimer mean clots? ›
A higher than normal D-dimer level might mean you have had a significant blood clot. However, the test does not tell where the clot was or what caused it. Other health problems can also cause the D-dimer level to go up.Is D-dimer always elevated with pulmonary embolism? ›
Abstract. The plasma level of D-dimer, a fibrin degradation product (FDP), is nearly always increased in the presence of acute pulmonary embolism (PE). Hence, a normal D-dimer level (below a cutoff value of 500 μ g/L by enzyme-linked immunosorbent assay [ELISA]) may allow the exclusion of PE.What is a good D-dimer number? ›
A normal D-dimer is considered less than 0.50. A positive D-dimer is 0.50 or greater. Since this is a screening test, a positive D-Dimer is a positive screen.Does a normal D-dimer rule out DVT? ›
The study results also show that normal D-dimer levels do not exclude distal DVT in outpatients; instead, it can be hypothesized that normal D-dimer levels exclude DVT that require treatment, as indicated by the good outcome in recent management studies.How can I lower my D-dimer naturally? ›
- Turmeric. Share on Pinterest Rowan Jordan/Getty Images. ...
- Ginger. ...
- Cayenne peppers. ...
- Vitamin E. ...
- Garlic. ...
- Cassia cinnamon. ...
- Ginkgo biloba. ...
- Grape seed extract.
Does water lower D-dimer? No, it does not. But becoming dehydrated lowers blood volume, and this makes your blood 'thicker' raising your risk for blood clots if you are predisposed.
Aspirin usually effects platelet interaction more than the clot formation itself. If anything as such, then it should increase the D-dimer.What are the warning signs of deep vein thrombosis? ›
- throbbing or cramping pain in 1 leg (rarely both legs), usually in the calf or thigh.
- swelling in 1 leg (rarely both legs)
- warm skin around the painful area.
- red or darkened skin around the painful area.
- swollen veins that are hard or sore when you touch them.
If not treated, a clot can break free and cause a pulmonary embolism—where the clot gets stuck in a blood vessel in the lung, causing severe shortness of breath and even sudden death. Treatment for blood clots depends on where the clot is in the body, and the severity of the condition.What does a leg clot feel like? ›
Signs that you may have a blood clot
leg pain or discomfort that may feel like a pulled muscle, tightness, cramping or soreness. swelling in the affected leg. redness or discoloration of the sore spot. the affected area feeling warm to the touch.
It's the standard test for diagnosing DVT . For the test, a care provider gently moves a small hand-held device (transducer) on the skin over the body area being studied. Additional ultrasounds may be done over several days to check for new blood clots or to see if an existing one is growing.
A blood clot in a leg vein may cause pain, warmth and tenderness in the affected area. Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in the body, usually in the legs. Deep vein thrombosis can cause leg pain or swelling. Sometimes there are no noticeable symptoms.Where is pulmonary embolism pain located? ›
Main symptoms of a pulmonary embolism include chest pain that may be any of the following: Under the breastbone or on one side. Sharp or stabbing. Burning, aching, or a dull, heavy sensation.What is the best diagnostic test for pulmonary embolism? ›
CTPA or a computed tomographic angiography is a special type of X-ray that is the most common test used to diagnose PE because it uses contrast to analyze blood vessels. D-Dimer blood tests to measure the amount of oxygen or CO2 in your blood. Chest X-ray of your heart and lungs.Where is lung pain felt? ›
Lung pain is often felt when you breathe in and out, either on one or both sides of your chest. Technically, the pain isn't coming from inside the lungs, since they have very few pain receptors. Instead, the pain may come from the lining of the lungs, which does have pain receptors.What does an early blood clot feel like? ›
It can cause pain, swelling, and red or dark, tender skin. The area around the blood clot may feel tight or sore like you have a muscle cramp or charley horse. Unfortunately, these symptoms of a blood clot can be confused with other conditions, including muscle pain and muscle injury.
This evaluation, known as Homan's Test, consists of laying flat on your back and extending the knee in the suspected leg. Have a friend or family member raise the extended leg to 10 degrees, then have them squeeze the calf. If there's deep pain in the calf, it may be indicative of DVT.Will blood clots go away on their own? ›
Blood clots can also cause heart attack or stroke. Blood clots do go away on their own, as the body naturally breaks down and absorbs the clot over weeks to months. Depending on the location of the blood clot, it can be dangerous and you may need treatment.