Causes of Elevated D-Dimer
D-dimer is elevated in acute thrombosis (DVT/PE) but also rises in numerous non-thrombotic conditions including malignancy, infection, pregnancy, post-surgery/trauma, inflammatory states, increasing age, disseminated intravascular coagulation, atrial fibrillation, and stroke, making it a sensitive but highly nonspecific marker. 1, 2
Thrombotic Causes
Venous Thromboembolism (VTE)
- Deep vein thrombosis (DVT) - D-dimer is typically elevated in acute DVT due to simultaneous activation of coagulation and fibrinolysis 1
- Pulmonary embolism (PE) - D-dimer levels are elevated in the presence of acute thrombosis, with high negative predictive value but low positive predictive value 2, 3
- Aortic dissection/aneurysm - Median D-dimer levels can reach 5.46 g/L in aortic aneurysm, showing excellent discrimination (AUC = 0.963) 4
Non-Thrombotic Medical Conditions
Malignancy
- D-dimer is more frequently elevated in patients with cancer, particularly those with metastatic disease or receiving chemotherapy 2
- Cancer represents one of the most common causes of ultra-high D-dimer levels (>5000 ng/mL) 5
Infectious and Inflammatory Conditions
- Severe infection or inflammatory disease - D-dimer testing has less usefulness in hospitalized and acutely ill patients due to high frequency of false-positive results 1
- Pneumonia - Frequently present when ultra-high D-dimer levels are encountered 5
- Respiratory infections - Median D-dimer levels of 0.76 g/L (IQR: 0.40-1.47 g/L) 4
- COVID-19 - Baseline D-dimer above upper limit of normal is associated with critical illness, thrombosis, acute kidney injury, and death; levels >5 mg/mL associated with remarkably high thrombotic risk 6
- Sepsis - Commonly associated with elevated D-dimer levels 5
Disseminated Intravascular Coagulation (DIC)
Physiologic and Age-Related Causes
Increasing Age
- The specificity of D-dimer in suspected PE decreases steadily with age to approximately 10% in patients >80 years of age 2, 3, 2
- Age-adjusted D-dimer cutoffs (age × 10 µg/L for patients >50 years) improve performance in elderly patients 2, 3, 2
Pregnancy
- D-dimer is more frequently elevated during pregnancy 2, 3, 2
- Pregnancy represents a physiologic condition associated with increased D-dimer levels 8
Exercise and Anxiety
Trauma and Surgery-Related Causes
Post-Surgical State
- D-dimer levels may be increased following surgery 1
- The number needed to test rises from 3 in general emergency department population to >10 in post-surgical patients 2
Trauma
- D-dimer levels are elevated following trauma 1
- In severely traumatized patients, tissue injury results in increased D-dimer levels above 500 ng/mL threshold that fail to normalize even after 14 days 10
- Mean ISS scores of 20 (range 4-50) associated with persistently elevated D-dimer 10
Cardiovascular Conditions
Atrial Fibrillation
- D-dimer levels may be increased in atrial fibrillation 1
Stroke
- D-dimer can be elevated in stroke patients 1
Hematologic Conditions
Leukemia
- D-dimer levels show superior discrimination for leukemia (AUC = 0.848) 4
Other Causes
Bleeding
- Associated with elevated D-dimer levels in hospitalized patients 5
Background Fibrinolytic Activity
- D-dimers in normal individuals can arise from background fibrinolytic activity in various tissues including kidney, mammary and salivary glands 9
- Minor injuries and wound healing with clot formation contribute to baseline D-dimer levels 9
Clinical Pitfalls
Important Caveats:
- In hospitalized and acutely ill patients, D-dimer testing has limited usefulness because of high frequency of false-positive results from the conditions listed above 1
- The positive predictive value of elevated D-dimer is low, making it not useful for confirmation of PE or DVT 2, 3, 2
- D-dimer testing demonstrates high variability within and among methods, requiring optimal cut-off adjustment based on assay methodology 6
- Ultra-high D-dimer levels (>15,000 ng/mL) without clear clinical diagnosis are associated with 75% mortality, indicating severe underlying disease 5