D-Dimer of 0.19 µg/mL FEU: Interpretation
Yes, a D-dimer of 0.19 µg/mL FEU is definitively negative and effectively rules out venous thromboembolism (VTE) in the appropriate clinical context.
Understanding the Result
Your D-dimer value of 0.19 µg/mL FEU falls well below the standard cutoff threshold of 0.5 µg/mL (500 ng/mL), which is used by highly sensitive assays to exclude VTE 1. This result carries a 99% negative predictive value when combined with low-to-moderate pretest probability of disease 1.
Clinical Context Matters
The interpretation depends critically on your pretest probability:
Low or Moderate Clinical Probability (Wells score ≤4 or "PE unlikely"): A negative D-dimer at 0.19 µg/mL safely excludes DVT or PE without need for imaging. The 3-month thromboembolic risk in patients left untreated based on this negative result is 0.1-0.6% 2.
High Clinical Probability: D-dimer should not be used to exclude VTE in this setting, as even highly sensitive assays have insufficient negative predictive value 1, 2. Proceed directly to imaging regardless of D-dimer result.
Assay Type Considerations
The reliability of your negative result depends on the assay sensitivity:
- Highly sensitive assays (ELISA-based like Vidas): Safe for excluding VTE in low-to-moderate probability patients 1
- Moderately sensitive assays (latex agglutination): Only safe for low probability patients 1, 2
Your value of 0.19 is so far below any threshold that it would be negative on any commercially available assay.
Age-Adjusted Interpretation
For patients over 50 years, an age-adjusted cutoff (age × 10 µg/L) can be applied 3, 4. For example:
- Age 60: cutoff = 600 µg/L (0.6 µg/mL)
- Age 75: cutoff = 750 µg/L (0.75 µg/mL)
Your value of 0.19 µg/mL would be negative at any age, making this adjustment unnecessary in your case.
Important Caveats
D-dimer has limited utility in certain populations where false positives are common 1, 2:
- Hospitalized patients
- Recent surgery or major trauma
- Active malignancy
- Pregnancy
- Advanced age (>80 years)
- Infection or inflammatory conditions
- Disseminated intravascular coagulation
However, your negative result remains valid even in these populations—the limitation applies primarily to positive results, which lose specificity.
Clinical Action
With a D-dimer of 0.19 µg/mL FEU:
If low-to-moderate pretest probability: VTE is effectively ruled out. No further imaging needed. Do not initiate anticoagulation 1, 5.
If high pretest probability: Proceed to compression duplex ultrasound for DVT or CT pulmonary angiography for PE, regardless of the negative D-dimer 1.
Document your clinical probability assessment using a validated tool (Wells score or Revised Geneva score) to justify your diagnostic approach 1, 2, 6.