A D-Dimer (Quantitative) test is a blood test that measures the amount of D-dimer in your bloodstream. D-dimer is a small protein fragment made when your body forms a blood clot and then breaks it down. In other words, it’s a marker of active clot formation and clot breakdown happening somewhere in the body.

This is called a “quantitative” D-dimer because it reports a number (the measured level), rather than just “positive/negative.” The result is most useful for helping clinicians rule out dangerous blood clots when your risk is otherwise low to moderate.

What results can mean (plain language):

Low/normal D-dimer: A low result makes an active, significant blood clot such as deep vein thrombosis (DVT) or pulmonary embolism (PE) much less likely—especially when combined with your symptoms and a clinical risk score. This is why it’s commonly used for DVT screening and PE evaluation in the emergency department or urgent care.

High/elevated D-dimer: A high result means there may be increased clotting activity, but it does not prove you have a clot. D-dimer can be elevated for many reasons (including recent surgery, infection, inflammation, pregnancy, liver disease, trauma, or simply older age). If your D-dimer is elevated and your symptoms suggest a clot, your clinician typically orders imaging tests (for example, ultrasound of the leg for DVT or CT pulmonary angiography for PE) to look for a blood clot.

The quantitative D-dimer test is usually ordered when a clinician needs to quickly assess whether symptoms could be caused by a blood clot and determine whether further testing is needed. It is most helpful when your pre-test probability is low to intermediate (based on your history, exam, and tools such as the Wells score or PERC criteria).

Symptoms that may prompt a D-dimer test include:

Possible DVT (clot in a deep vein, often in the leg): one-sided leg swelling, pain or tenderness (often in the calf), warmth, redness/discoloration, or a leg that suddenly feels tight.

Possible pulmonary embolism (clot in the lung): sudden shortness of breath, chest pain that may worsen with deep breathing, fast heart rate, unexplained cough (sometimes with blood), lightheadedness, or fainting.

Possible disseminated intravascular coagulation (DIC) or abnormal clotting/bleeding: unusual bleeding or bruising, very low blood pressure in severe illness, organ dysfunction signs, or lab patterns suggesting widespread clotting and bleeding. In suspected DIC, D-dimer is typically interpreted alongside platelet count, PT/INR, aPTT, and fibrinogen.

Risk factors that may increase concern for blood clots and lead to testing include: recent surgery or hospitalization, prolonged immobility (long flights/car rides or bed rest), pregnancy and the postpartum period, use of estrogen-containing birth control or hormone therapy, active cancer, prior DVT/PE, inherited clotting disorders, smoking, obesity, and significant trauma.

Clinicians may also use age-adjusted thresholds in appropriate patients, because D-dimer levels can rise with age. Your provider will interpret your result in context rather than relying on a single number.

• Deep vein thrombosis (DVT)
• Pulmonary embolism (PE)
• Venous thromboembolism (VTE)
• Disseminated intravascular coagulation (DIC)
• Sepsis and severe systemic infection (may elevate D-dimer)
• Recent surgery or major trauma (post-operative/post-injury clotting activity)
• Pregnancy-related hypercoagulability (D-dimer may be elevated)
• Active cancer–associated thrombosis
• Liver disease (can affect clotting and D-dimer levels)

• Ruling out a suspected blood clot (DVT screening) when symptoms are concerning but risk is low to moderate
• Evaluating symptoms that could be a pulmonary embolism (PE), such as sudden shortness of breath or chest pain
• Supporting timely decisions about whether imaging is needed (ultrasound or CT) during urgent evaluation
• Monitoring clotting-related complications during severe illness (e.g., suspected DIC) as part of a broader coagulation workup
• Improving patient safety by helping avoid unnecessary scans and radiation/contrast exposure when the D-dimer is negative and clinical risk is low