D-Dimer
- Sample Type
- Plasma (Citrate)
- Fasting
- No
- Unit
- ng/mL FEU
Function
D-Dimer is a protein fragment (fibrin degradation product) that is made when a blood clot dissolves in the body. It is normally undetectable or present at very low levels unless the body is actively forming and breaking down blood clots.
Why it is Ordered
The primary clinical use of the D-Dimer test is to 'rule out' inappropriate blood clots. It is used in emergency settings to evaluate patients suspected of having Deep Vein Thrombosis (DVT), Pulmonary Embolism (PE), or Disseminated Intravascular Coagulation (DIC).
Associated Conditions
- Venous Thromboembolism (VTE): Includes DVT and PE.
- DIC: A complex condition where blood clots form throughout the body, followed by bleeding.
- Malignancy: Certain cancers can activate the coagulation system.
- Sepsis: Severe infections often trigger systemic clotting and fibrinolysis.
Clinical Importance
D-Dimer is highly sensitive but poorly specific. This means that while a negative result is very reliable for ruling out a clot, a positive result does not prove a clot is present. It merely indicates that fibrin degradation is occurring, which can happen for many reasons, including recent surgery, trauma, or inflammation.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
D-Dimer levels naturally increase with age, often leading to false positives in elderly patients without clots. Furthermore, pregnancy, recent trauma, surgery, and systemic inflammatory diseases (like Rheumatoid Arthritis) can all cause elevated D-Dimer levels. If a test is positive without classic symptoms of a clot, clinical correlation and imaging (like an ultrasound or CT) are mandatory.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for D-Dimer:
Official Sources
Research & Guidelines
- PubMed: D-Dimer Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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