D-Dimer Test for Blood Clots: Test Purpose, Understanding the Test Results & Cost

A cut, scrape, or injury that manages to break the skin and cause one to bleed triggers a sequence of steps in the body, which form a blood clot to block the cut. Once the wound has healed, the body dissolves the blood clot through fibrinolysis, which results in the release of the D-dimer protein fragments in the blood. D-dimer is a leftover product of fibrin degeneration that remains in the body for around 8 hours after being formed, till the time the kidneys filter it out of the body. The normal level of D-dimer is either undetectable or very low. The D-dimer test is performed to measure the levels of this protein in the body and is the first line of assessment for individuals suspected to suffering from venous thromboembolism or other blood clotting disorders.

The Purpose of the D-Dimer Test

If an individual has a blood clotting disorder, the blood may start forming clots, even without an injury or proper clots may not be getting dissolved after healing. High levels of D-dimer are generally caused by the body constantly making and breaking down blood clots, without an injury, or if a formed clot does not dissolve properly even after healing. D-dimer has also been known to be high in the case of COVID-19 and has been associated with how severe the infection may be. It is a practice at several healthcare institutions to perform the D-dimer test for COVID-19 patients being admitted to get a better idea of their health status.

An individual may be prescribed to undergo a d-dimer test at a lab if their doctor suspects a blood clotting disorder. The d-dimer test result can help confirm as well as rule out clotting disorders, like:

Deep Vein Thrombosis (DVT): This is a condition that involves a blood clot situated deep inside a vein. These clots generally affect the lower legs of an individual but can occur in other parts as well. Symptoms of DVT include swelling, redness, and pain.
Pulmonary Embolism (PE): Thisis a condition in which a blood clot reaches your lungs and gets lodged in one of the blood vessels there. Symptoms of PE include trouble breathing, coughing, pain in the chest, and a fast heartbeat.
Disseminated Intravascular Coagulation (DIC): This is when the body is forming too many blood clots, which may lead to organ damage and other serious complications. Bleeding from many sites in the body, drops in blood pressure, bruising, shortness of breath, change in behaviour, memory loss, confusion, and blood clots are symptoms that may indicate DIC. Apart from checking for blood clots, the D-dimer test can also be prescribed to monitor the efficacy of a DIC treatment plan.
Stroke: The blocking or bursting of a blood vessel in the brain can lead to a stroke. Symptoms of the same include sudden weakness or numbness in the face, leg, arm (especially in one side of the body), sudden difficulty in speaking, sudden confusion, trouble seeing from one eye, difficulty in walking, dizziness, etc.

Other uses of a d-dimer test include treatment monitoring for various diagnosed blood clotting disorders. Checking for the normal range of D-dimer is only helpful if an individual is not very likely to have blood clots, as a positive test result may not always indicate the same. If one has higher odds of having blood clots, they will be prescribed different tests. The risk factors of having blood clots include:

Congenital clotting disorders
Anti-phospholipid syndrome
Having undergone major surgery, like knee replacement
Having had a major injury, like fractures
Just having been through long periods of having to sit down, like a hospital stay or even a long plane ride
Pregnancy or a recent delivery
Certain cancers

Before Undergoing the D-Dimer Blood Test

There are no particular preparations, like overnight fasting, that an individual has to undergo before getting the test performed. The test itself involves the collecting of a blood sample from a vein in the arm using a needle, and can be performed at any accredited lab. In fact, one can always check the price of the D-dimer test online before booking it at a nearby diagnostics centre. However, as every individual’s health status is different, it is always better to consult a doctor regarding any precautions that may be required before the D-dimer blood test.

Understanding the Test Results

Various labs may define the normal range for the D-dimer test differently, so it is always better to consult a doctor with the results to get a better understanding of what they mean. In general, a ‘negative’ result indicates that the individual does not have any blood clot-related issues like DVT. On the other hand, while ‘positive’ or ‘high’ results may indicate the presence of a blood clotting disorder, a D-dimer test cannot diagnose what the disorder is or even where the blood clot is present. A high or positive result generally means that further testing will be required for a diagnosis of the disorder.

Blood clotting is a common and often lifesaving function of the body but if blood clots start forming without any reason or if they fail to dissolve even after healing, they can lead to a number of major complications as well.