D-Dimer
D-Dimer test measures protein fragments from blood clot breakdown to screen for thrombosis, pulmonary embolism, and blood clotting disorders.
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Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
D-dimer is a protein fragment that appears in the blood when a blood clot breaks down. Under normal circumstances, the body forms clots to stop bleeding at injury sites, using fibrin strands to hold the clot together. Once healing is complete, the body dissolves the clot, and the degradation of that fibrin network produces D-dimer fragments that enter the bloodstream before being cleared.
The D-dimer test is most valuable as a rule-out tool. It has high sensitivity (meaning it reliably detects clotting activity when it is occurring) but low specificity (meaning an elevated result can be caused by many conditions besides dangerous clots). A normal or negative D-dimer result is clinically powerful because it makes active thrombotic conditions like deep vein thrombosis (DVT), pulmonary embolism (PE), and disseminated intravascular coagulation (DIC) unlikely. An elevated result, however, requires further investigation, since surgery, pregnancy, infection, inflammation, and even advanced age can raise D-dimer levels.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing symptoms that may suggest deep vein thrombosis, such as unexplained swelling, pain, or tenderness in the legs, particularly when these symptoms occur suddenly or worsen over time.
- Those with suspected pulmonary embolism who may be experiencing symptoms like sudden shortness of breath, chest pain, rapid heart rate, or coughing that cannot be explained by other conditions.
- Patients being evaluated for disseminated intravascular coagulation (DIC), particularly those with underlying conditions such as severe infection, trauma, or certain cancers that can trigger this serious clotting disorder.
- Individuals with risk factors for blood clots, including recent surgery, prolonged immobilization, pregnancy, hormone therapy, certain medications, or a personal or family history of clotting disorders.
- People seeking to rule out blood clotting disorders when other clinical assessments suggest a low to moderate probability of thrombotic disease, as this test is most effective when used in conjunction with clinical evaluation.
What to expect
Preparation
No special preparation is required for the D-Dimer test. Fasting is not necessary, and individuals can maintain their normal diet and activities before testing. It may be helpful to inform healthcare providers about any medications being taken, particularly blood thinners or anticoagulants, as these may affect interpretation of results.
Sample Type
The D-Dimer test requires a simple blood draw from a vein, typically from the arm. The sample is collected in a special tube containing sodium citrate to preserve the blood for coagulation testing.
Collection
At the lab location, a trained phlebotomist will clean the injection site and insert a needle to draw blood into the collection tube. The process typically takes just a few minutes and involves minimal discomfort. The collected sample is then sent to the laboratory for analysis.
Turnaround
Results are typically available within 1-2 business days after the laboratory receives the sample. Results will be provided through the secure online portal, with no doctor visit required to receive or interpret the basic findings.
Understanding your results
D-dimer testing methodologies vary between laboratories, so there is no single universal reference range. Results may be reported as a numerical concentration or categorized as positive/negative (or detected/not detected). A normal, low, or negative result is the most clinically actionable outcome: it typically allows healthcare providers to rule out active blood clotting conditions with high confidence. An elevated or positive result does not confirm a clot but signals the need for additional diagnostic evaluation, such as imaging studies, to determine the cause. Healthcare providers interpret D-dimer alongside symptoms, clinical risk assessment, and other laboratory findings.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | Less than 500 ng/mL (or 0.5 mg/L FEU) | Normal range may vary by laboratory and testing method used |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Low, negative, or normal D-dimer levels typically indicate that significant blood clotting disorders are unlikely to be present. A normal D-dimer result has approximately a 95% negative predictive value for ruling out acute pulmonary embolism or deep vein thrombosis when there is low or moderate pretest probability. For individuals previously diagnosed with disseminated intravascular coagulation who are undergoing treatment, normal or low levels may suggest that treatment is working effectively.
What does a “High” result mean?
Elevated D-dimer levels may indicate the presence of a blood clotting condition, but this does not guarantee that a clot is present. Higher levels can suggest conditions such as deep vein thrombosis, pulmonary embolism, or disseminated intravascular coagulation. However, many other conditions can also cause elevated D-dimer levels, including pregnancy, recent surgery, trauma, liver disease, inflammation, and certain medications. Additional testing is typically needed to confirm or rule out specific clotting disorders when D-dimer levels are elevated.
Privacy & confidentiality
All D-Dimer test results are completely confidential and protected under HIPAA regulations. Results are not shared with your personal physician unless you choose to share them, are not added to your medical records, and do not appear on insurance statements or explanations of benefits.
Frequently asked questions
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Last reviewed: April 2026
CPT Code: 85378
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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