A D-dimer test is a blood test used to check for blood clotting problems.
Blood clots can cause health problems, such as:
- Deep vein thrombosis (DVT)
- Pulmonary embolism (PE)
- Disseminated intravascular coagulation (DIC)
- Stroke
A D-dimer test may be indicated in people who have symptoms of blood clots, such as:
- Swelling, pain, warmth, tenderness to the touch, and redness in the affected area
- Swelling in the leg or arm
- Changes in skin color of a leg or arm
- Cramp-like feeling
- Sharp chest pain
- Fast heart rate
- Palpitations
- Numbness or weakness on one side of the body
- Abrupt change in mental status
- Bleeding gums
- Nausea and vomiting
- Severe stomach pain
- Severe muscle pain
- Decreased urine
- Seizures
If a blood clot breaks off and travels to the lung, this is called a pulmonary embolism (PE), which is a medical emergency and can be fatal. Go to a hospital’s emergency department immediately (do not drive yourself) if you have symptoms of pulmonary embolism such as:
- Shortness of breath/trouble breathing with no known cause
- Unexplained cough
- Coughing up blood
- Chest pain
- Increased heart rate
- Fatigue
- Passing out (syncope)
A D-dimer test may also be used to see if treatment for disseminated intravascular coagulation (DIC) is working.
What Are Normal Results of a D-Dimer Test?
- A normal D-dimer test result is negative and means problems with blood clotting are unlikely.
- If the D-dimer test is used to check if treatment is working for disseminated intravascular coagulation (DIC), a normal or decreasing level of D-dimer means the treatment is working.
What Do Abnormal Results of a D-Dimer Test Mean?
An abnormal D-dimer test result would be positive, and it would signify the person may be producing blood clots. A D-dimer test does not tell where the clots are or why they are being produced.
Other tests are needed to see where clots are located.
D-dimer levels can be positive even when no blood clots are present due to other factors, such as:
- Age over 80 years
- Heart disease
- High lipid or triglyceride levels
- Liver disease
- Recent surgery or trauma
- Pregnancy
What Causes Blood Clots?
Causes of a blood clot in a vein (venous thrombosis) include:
- Injury to the leg veins
- Illness that affects the veins
- Immobility
- Broken bone
- Certain medications
- Obesity
- Inherited (genetic) disorders
- Autoimmune disorders that increase the risk of blood clots
- Medicines that increase the risk of blood clots (such as certain birth control hormones)
Causes of a blood clot in an artery (arterial thrombosis) include:
- Injury to the artery
- Infections such as sepsis or viral infections
- Hardening of the arteries (atherosclerosis)
- If this occurs in the coronary arteries it can lead to a heart attack
- If this occurs in a blood vessel in the brain, it can lead to a stroke
Risk factors for both venous and arterial thrombosis include:
- Family history or personal history of blood clots such as deep vein thrombosis (DVT)
- Immobility, such as from long flights or after surgery
- Older age
- Smoking
- Being overweight or obese
Additional risk factors for venous thrombosis include:
- Use of birth control pills or hormone therapy
- Pregnancy
- Injury to a vein, which may occur from surgery, a broken bone, or other trauma
- Inherited blood clotting disorders
- A central venous catheter
- Certain conditions, such as cancer, heart disease, lung disease, or Crohn's disease
Additional risk factors for arterial thrombosis include:
- Diabetes
- High blood pressure (hypertension)
- High cholesterol
- Sedentary lifestyle
- Poor diet
Image source: iStock Images
https://www.uptodate.com/contents/deep-vein-thrombosis-dvt-beyond-the-basics?search=thrombus&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
https://www.nhs.uk/conditions/blood-clots/
https://www.hopkinsmedicine.org/health/conditions-and-diseases/thrombosis