Why is the D-Dimer Test Done? healthcare nt sickcare

Why is the D-Dimer Test Done?

The D-dimer test is performed for several reasons related to the detection and evaluation of blood clotting disorders. This blood test measures the level of D-dimer, which is a protein fragment produced by the body when a blood clot dissolves.

Why is the D-Dimer Test Done?

Here are some key reasons why the D-dimer test is done:

  1. Blood Clot Detection: The primary purpose of the D-dimer test is to help diagnose or rule out the presence of blood clots in the body. Elevated D-dimer levels indicate that blood clots are being formed and dissolved in significant amounts. This test is particularly useful in the evaluation of deep vein thrombosis (DVT) and pulmonary embolism (PE), which are serious conditions involving blood clots.
  2. Evaluation of Thrombosis Risk: The D-dimer test is also used to assess the risk of thrombosis in certain situations. For example, it can be performed before surgery or in hospitalized patients to determine the likelihood of blood clots forming. Additionally, it helps monitor individuals with conditions that predispose them to abnormal blood clotting, such as atrial fibrillation, cancer, or inherited clotting disorders.
  3. Exclusion of Clotting Disorders: In some cases, the D-dimer test is employed to exclude the presence of blood clotting disorders. A normal D-dimer level suggests that a clotting problem is unlikely, which can be valuable in ruling out certain conditions and guiding further diagnostic investigations.
  4. Supportive Test: The D-dimer test is often used in conjunction with other blood tests and imaging scans to aid in the diagnosis of blood clot-related conditions. It provides additional information and helps healthcare professionals make more accurate assessments. It's important to note that the D-dimer test alone cannot determine the location of blood clots or the underlying cause of clot formation.

In summary, the D-dimer test is performed to detect and evaluate blood clotting disorders, primarily deep vein thrombosis and pulmonary embolism. It helps diagnose, assess the risk of thrombosis, excludes clotting disorders, and supports other diagnostic procedures. However, it's essential to interpret the D-dimer test results in conjunction with clinical findings and additional investigations for an accurate diagnosis.

D-Dimer Test for Deep Vein Thrombosis

The D-dimer test is commonly used in the evaluation of deep vein thrombosis (DVT), a condition characterized by the formation of blood clots in the deep veins, usually in the legs. When a blood clot forms in the body, certain proteins, including D-dimer, are released as the clot dissolves. The D-dimer test measures the level of these protein fragments in the blood, which can indicate the presence of blood clots.

When it comes to DVT, the D-dimer test is particularly useful as a screening tool to rule out the condition in individuals suspected of having it. A negative or normal D-dimer result is highly indicative that a DVT is unlikely. This is because a negative result suggests that the D-dimer level is either undetectable or only present at a very low level, which indicates that there is no significant formation and breakdown of blood clots occurring in the body.

However, it's important to note that a positive D-dimer result does not necessarily confirm the presence of DVT. A positive result indicates that D-dimer is detectable in the blood, but it doesn't specify the location or cause of the blood clot. Therefore, additional diagnostic tests such as ultrasound imaging or venography are usually required to confirm or rule out DVT in individuals with a positive D-dimer test.

The D-dimer test is often used in combination with other clinical assessments and imaging techniques to aid in the diagnosis of DVT. It helps healthcare professionals decide whether further diagnostic investigations are necessary, and can also be used to monitor the effectiveness of treatment in individuals diagnosed with DVT.

In summary, the D-dimer test is frequently utilized as a screening tool for deep vein thrombosis. A negative or normal D-dimer result suggests that DVT is unlikely, while a positive result warrants further evaluation through imaging tests to confirm or exclude the presence of blood clots in the deep veins.

How to Test for D Dimer?

D-dimer is a protein fragment produced when a blood clot dissolves in the body. Detection of elevated D-dimer indicates increased clot formation and breakdown.

Sample Type

It requires a simple blood sample, usually collected by a routine venous blood draw from the arm. Very rarely, a citrated plasma sample collected via specialized tube may be needed.

Testing Methods

Common methods used are -

  1. Enzyme-linked immunosorbent assay (ELISA)
  2. Quantitative rapid assay using latex agglutination pathways
  3. Point-of-care immunoassay using capillary blood from fingerprick

These provide a quantitative result signaling how high above normal threshold the D-dimer level is.


Raised levels correlate to increased thrombosis risk profiling. A normal result along with clinical findings helps rule out deep vein thrombosis or pulmonary embolism. Elevation supports diagnosis.

So in summary, D-dimer analysis via immunoassays on blood sample aids thrombosis risk stratification and diagnosis. It provides key supportive evidence for clinical decision making regarding anticoagulation needs.

What is D-dimer, and why is it tested?

D-dimer is a protein fragment present in the blood after a blood clot breaks down. A D-dimer test helps check for blood clots and can support diagnosis of conditions like deep vein thrombosis, pulmonary embolism, or disseminated intravascular coagulation.

When is the D-dimer level high?

D-dimer levels are elevated when substantial clot formation and fibrinolysis has occurred recently in the body. Levels can increase with recent surgery, trauma, infection, some cancers, pregnancy, etc. An abnormal D-dimer level warrants further testing for blood clots.

What conditions are checked for with a D-dimer test?

The D-dimer test may be ordered if a doctor suspects thrombosis issues like DVT, PE or DIC based on symptoms such as swelling, chest pain, shortness of breath. It helps rule out clot presence and guide clinical management. Elevated levels call for further imaging tests.

How do doctors diagnose blood clots?

Doctors synthesize D-dimer test results with patient risk factors, symptoms, physical exam findings and other lab work and imaging such as ultrasound or CT scan. Only imaging studies can definitively diagnose most dangerous blood clots. A normal D-dimer makes clots highly unlikely.

Is the D-dimer test accurate?

The D-dimer has high sensitivity and will be elevated with clots, but it has relatively low specificity as many other conditions can raise levels. Results must be carefully interpreted in clinical context. Follow-up tests are often needed to confirm or exclude blood clot presence.


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