Key Takeaways
✅ D-dimer is a plasmin-derived soluble degradation product of cross-linked fibrin.
✅ There are many causes for an elevated D-dimer level, including thrombotic and non-thrombotic conditions, such as:
- Malignancy
- Inflammation
- Infection, including COVID19
- Pregnancy
- Liver disease
- Elderly
✅ D-dimers are most useful:
- In diagnostic algorithms to exclude a diagnosis of venous thromboembolism (VTE) in those with low clinical probability for this condition.
- To determine the optimal duration of anticoagulation in VTE patients (especially women).
- In the diagnostic algorithm for disseminated intravascular coagulation DIC.
✅ Assays include:
- Whole blood agglutination assays
- Enzyme-linked immunosorbent assays (ELISA)
- Enzyme-linked immunofluorescent assays (ELFA)
- Latex agglutination assays
✅ ELISA, ELFA, and quantitative latex agglutination assays were more sensitive than whole-blood agglutination assays . Therefore, unless other assays are unavailable, the whole-blood D-dimer assay should not be used.
✅ Normal plasma levels of D-dimer by ELISA testing are <500 ng/mL for fibrin equivalent units (FEU) or <250 ng/mL for D-dimer units (DDU).