D-dimer is a protein fragment produced by blood clots. To detect it, there is a test that evaluates whether a person has D-dimer in normal values, and serves mainly to reveal if you have a coagulation disorder in the blood. In this post, we will provide you with all the information you need to know about the D-dimer test and what normal values of this protein determine.
What is the D-dimer test and what is it for?
When a person is injured, a clot is generated through a process called hemostasis that prevents excessive bleeding. This is where strands known as fibrins act to hold the clot in place until the wound heals. Once the injury is healed, the blood clot breaks into small fragments and dissolves in the body. This is precisely where D-dimer is produced. However, the problem arises when there is significant clot disintegration in the body, as D-dimer levels can become elevated.
The D-dimer test is very useful to record whether you have normal values of this protein, and to rule out the presence of a thrombus or clot. This is very important, because if a person has problems with blood clotting, he or she can suffer serious health problems. If the results show elevated blood D-dimer values, that person may have deep vein thrombosis (DVT), pulmonary thromboembolism (PTE), cerebrovascular accident (CVA) or disseminated intravascular coagulation (DIC).
How is the D-dimer test performed?
The D-dimer test is performed through a venous blood sample and requires no special preparations. It is a simple and quick test that rules out abnormal or excessive clotting. The test is indicated for particular cases in which there are symptoms suggestive of a disease or thrombotic episode such as tenderness, swelling, pain, redness or depigmentation in the legs. Generally, clots are generated in the lower extremities of the body, however, they can also form in other sites, such as in the arteries of the heart, triggering a myocardial infarction, or in the valves or inner wall of the heart. If the patient suffers from a pulmonary embolism, he/she usually has an increased respiratory rate, pain and shortness of breath and cough with the possibility of blood in the sputum. If suffering from disseminated intravascular coagulation, some of the most frequent symptoms are bleeding gums, vomiting, and severe muscle and abdominal pain.
What are the different possible test results?
If you have low or normal D-dimer values, it is assumed that you do not have a blood clotting disorder. On the other hand, if the values are high, other tests should be done to make a proper diagnosis and find the cause of this increase in values. Increased D-dimer levels may not be due to a clotting disorder, but to other situations such as pregnancy, recent surgery, trauma, or diseases in which fibrin is not properly removed from the blood. It is for this reason that the D-dimer test is not usually used to rule out venous thrombolysms in people who have been hospitalized. In addition, elderly people, as well as people with rheumatoid arthritis, may have elevated D-dimer.
As mentioned above, because the D-dimer test is of low specificity, other more specific tests must be performed to make an accurate diagnosis. Additional tests that will be indicated by the physician to find the cause, such as a Doppler ultrasound or CT angiography, will seek to rule out the existence of the aforementioned blood coagulation disorders.
Issues to keep in mind
In relation to these disorders, we can mention some issues that are important to keep in mind:
- Deep vein thrombosis (DVT) usually affects the legs, and is generated by a clot in a deep vein that blocks blood flow in the area.
- Pulmonary thromboembolism (PTE), on the other hand, occurs when the clot generated in a specific part of the body breaks loose and reaches the lung, blocking an artery in the lung.
- Cerebrovascular accident (CVA) occurs when the blood supply to the brain is cut off due to a clot.
- Finally, disseminated intravascular coagulation (DIC) generates clots in different parts of the body and causes multiple complications. DIC is a complex acute situation that can be caused by surgery, liver disease and during postpartum.
What risk factors are associated with a blood clotting disorder?
As we have seen throughout this article, infections, surgeries, pregnancy, or liver problems can generate an increase in D-dimer. Below, we mention other risk factors that are commonly related to a blood clotting problem:
- Bone fractures
- Cancer
- Obesity
- Use of birth control pills
- Smoking
- Sedentary lifestyle or extended immobility
- Antiphospholipid syndrome
- Inherited blood clotting disorders
D-dimer tests are very useful to detect any blood clotting disorder and prevent critical health situations. Contact us if you have any questions and visit our blog to keep up to date with all the latest news in the clinical field.
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