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D-Dimer
Aka: D-Dimer, D Dimer, D-Dimer Discriminatory Values in Pulmonary Embolism
- See Also
- Deep Vein Thrombosis (DVT)
- Pulmonary Embolism Diagnosis
- Indication
- Suspected Venous Thrombosis (DVT)
- Suspected Pulmonary Embolism (Low PE Probability)
- See Pulmonary Embolism Diagnosis
- Used in conjunction with non-invasive studies
- Reduces the need for angiography
- Consider using to risk stratify after Thromboembolism
- High D-Dimer at one month predicts recurrence
- Efficacy
- Precautions
- Negative D-Dimer is reassuring if low probability
- Use more specific tests if suspicion is high
- Positive D-Dimer has minimal clinical value
- Positive does not raise DVT or PE Probability
- Test Sensitivity: 93% for Venous Thromboembolism
- Test Specificity: 25% for Venous Thromboembolism
- Negative Predictive Value: 99.5% if Low PE Probability
- Wells (2001) Ann Intern Med 135:98-107 [PubMed]
- Labs: Measurement
- ELISA assay and advanced turbidimetric
- Most sensitive D-Dimer Assays
- Rapid Latex Agglutination
- First generation tests were variable
- Second generation tests appear to be adequate and similar to ELISA
- Labs: Quantitative Assay Units
- Fibrinogen Equivalent Units (FEU)
- Newer measurement units that replace the older DDU
- FEU = 2 * DDU
- FEU Units are used for cutoffs described below
- D-Dimer Units (DDU)
- Older standard units replaced by the newer FEU
- Mechanism
- Marker for intravascular coagulation
- D-Dimer is degradation product of Fibrin
- Indicates plasmin lysis of Fibrin
- Presence of D-Dimer suggests thrombosis
- Labs: Normal
- Negative Test: D-Dimer <500 ng/ml (default, lab reported normal cutoff)
- Discriminatory value in low risk Pulmonary Embolism
- Cutoff <500 ng/ml
- Adults at age <50 years
- First trimester pregnancy
- Any age with YEARS Score with any of 3 criteria present
- Moderate Probability on Wells Clinical Prediction Rule for PE (PEGeD protocol)
- Cutoff <600 ng/ml
- Adults at age 60 to 70 years (ACP age-adjusted D-Dimer)
- Cutoff <700 ng/ml
- Adults at age 70 to 75 years (ACP age-adjusted D-Dimer)
- Cutoff <750 ng/ml
- Second trimester pregnancy
- Cutoff <1000 ng/ml
- Adults at age >75 years
- Third trimester pregnancy
- Low Probability on Wells Clinical Prediction Rule for PE (PEGeD protocol)
- Any age with YEARS Score with all criteria absent
- In addition to YEARS Score, several studies have used D-Dimer 1.0 for low risk cases at any age
- Kearon (2019) N Engl J Med 381(22): 2125-34 +PMID:31774957 [PubMed]
- Freund (2021) JAMA 326(21): 2141-9 [PubMed]
- References
- ACP recommends Adult, age-adjusted D-Dimer cut-off
- Age >50 years old: Threshold = Age X 10 ng/ml
- Raja (2015) Ann Intern Med 163(9): 701-11 +PMID:26414967 [PubMed]
- D-Dimer Cutoff of 1000 ng/ml in age over 80 years old has 100% Test Sensitivity
- Polo Friz (2014) Thromb Res 133(3): 380-3 [PubMed]
- Pregnancy related D-Dimer cutoffs
- Chan (2010) J Thromb Haemost 8(5): 1004-11 +PMID:20128870 [PubMed]
- Ercan (2014) J Matern Fetal Neonatal Med 25:1-5 +PMID:25060670 [PubMed]
- Kovac (2010) Eur J Obstet Gynecol Reprod Biol 148(1): 27-30 +PMID:19804940 [PubMed]
- Pulmonary Embolism Graduated D-Dimer (PEGeD) Protocol
- Kearon (2019) N Engl J Med 381(22): 2125-34 [PubMed]
- Causes: Increased D-Dimer (not specific)
- Venous Thromboembolism (true positive)
- Pulmonary Embolism
- Deep Vein Thrombosis
- Other causes (False Positives)
- Recent surgery (within prior 1 week)
- Myocardial Infarction
- Atrial Fibrillation
- Infection or Sepsis
- Cancer
- Concurrent systemic illness
- Oral Anticoagulant use
- Pregnancy
- Ongoing blood loss
- Decreased Renal Function
- Disadvantages: Circumstances in which D-Dimer is less useful
- Concurrent Anticoagulant use
- Comorbid cancer
- Age over 70 years
- Post-surgical status
- References
- Schutgens (2002) Am J Med 112:617-21 [PubMed]
- Lippi (2001) Clin Exp Med 1(3):161-4 [PubMed]
- References
- Orman and Berg in Herbert (2015) EM:Rap 15(5): 10-11