Widely Used Types and Clinical Applications of D-Dimer Assay

A Test in Context: D-Dimer

D-dimer is a soluble fibrin degradation product that results from ordered breakdown of thrombi by the fibrinolytic system. Numerous studies have shown that D-dimer serves as a valuable marker of activation of coagulation and fibrinolysis. Consequently, D-dimer has been extensively investigated for the diagnosis of venous thromboembolism (VTE) and is used routinely for this indication. In addition, D-dimer has been evaluated for determining the optimal duration of anticoagulation in VTE patients, for diagnosing and monitoring disseminated intravascular coagulation, and as an aid in the identification of medical patients at high risk for VTE. Thus, quantification of D-dimer levels serves an important role in guiding therapy. This review: 1) describes how D-dimer is generated; 2) reviews the assays used for its detection; and 3) discusses the role of D-dimer determination in these various conditions.

Assessment of regional fibrinolytic activity of tear fluid by determining the levels of D-dimer in patients with retinal vein occlusion

First defined level of D-dimer in the tear fluid in order to assess regional fibrinolytic activity in patients with retinal vein occlusion. It is shown that normally the level of D-dimer in tear fluid significantly higher than in blood plasma. It has been found to have elevated levels of D-dimer tear fluid in patients with CRVO and BRVO, which may indicate the activation of fibrinolysis, as a component of the inflammatory response. In appointing the anticoagulant and fibrinolytic therapy have a tendency to normalization of D-dimer in the tear fluid.

Troponin I and D-Dimer for Discriminating Acute Pulmonary Thromboembolism from Myocardial Infarction

BACKGROUND

Acute pulmonary thromboembolism (APTE) is a life-threatening condition, often manifesting with chest pain, dyspnea, and increased cardiac biomarkers including cardiac troponin I (CTI) and D-dimer. Therefore, APTE is often misdiagnosed with classical non-ST elevation myocardial infarction (NSTEMI), resulting in unnecessary coronary interventions and a delay of therapy.

OBJECTIVES

Our aim was to distinguish APTE from NSTEMI based on CTI and D-dimer levels.

METHODS

Complete clinical and laboratory data sets from APTE patients (n = 123) were compared with matched NSTEMI patients (n = 123) who presented with chest pain. The APTE diagnosis was confirmed by chest tomography, angiography, or radionuclide ventilation-perfusion scan, while NSTEMI was established by clinical symptoms, cardiac biomarkers, and coronary angiography. Clinical characteristics, CTI (initial and peak), and D-dimer levels at presentation were retrospectively analyzed.

RESULTS

The clinical characteristics were not different between APTE and NSTEMI patients. However, significantly lower initial CTI (0.2 ± 0.5 vs. 4.4 ± 9.5 ng/ml) and peak CTI (0.7 ± 2.7 vs. 17.1 ± 20.4 ng/ml), but higher initial D-dimer (9.8 ± 9.4 vs. 1.6 ± 3.6 ng/ml), distinguished APTE from NSTEMI. By receiver operating characteristic curve analysis, the cutoff values for initial CTI, peak CTI, and D-dimer were 0.25, 0.98, and 3.18 ng/ml, respectively.

CONCLUSION

Patients with APTE exhibited lower initial and peak CTI but higher D-dimer levels than NSTEMI patients. Assessing cardiac biomarkers is useful for differentiating APTE from NSTEMI. Further large randomized biomarker studies are urgently needed to facilitate a better APTE diagnosis since clinical characteristics are not particularly helpful.