D-Dimer Test
The NADAL® D-Dimer Test is used for the qualitative detection of D-Dimer in human whole blood and plasma. The test is used as an aid in the assessment and evaluation of patients with suspected disseminated intravascular coa-gulation (DIC), deep vein thrombosis (DVT) and pulmonary embolism (PE)
During blood coagulation process, fibrinogen is converted to fibrin by the activation of thrombin. The resulting fibrin monomers polymerise to form a soluble gel of non-cross- linked fibrin. This fibrin gel is then converted to cross-linked fibrin by thrombin activated factor XIII to form an insoluble fibrin clot. Production of plasmin, the major clot-lysing enzyme, is triggered when a fibrin clot is formed. Although fibrinogen and fibrin are both cleaved by the fibrinolytic enzyme plasmin to yield degradation products, only degradation products from cross-linked fibrin contain D-Dimer and are called cross-linked fibrin degradation products. Therefore, fibrin derivatives in human blood or plasma containing D-Dimer are a specific marker of fibrinolysis.
The detection limit of the NADAL® D-Dimer Test is 500 ng/mL D-Dimer.
The NADAL® D-Dimer Test (whole blood/ plasma) detects D-Dimer through visual interpretation of color development in the internal strip. Anti-D-Dimer antibodies are immobilized on the test region of the membrane, and anti-mouse antibodies are immobilized on the control region. During testing, the specimen reacts with anti-D-Dimer antibodies conjugated to colored particles and precoated onto the specimen pad of the strip. The mixture then migrates through the membrane by capillary action and interacts with reagents on the membrane. If there is sufficient D-Dimer in the specimen, a colored band will form at the test region of the membrane. The presence of this colored band indicates a positive result, while its absence indicates a negative result. The appearance of a colored band at the control region serves as a procedural control, indication that the proper volume of specimen has been added and membrane wicking has occurred.
Elevated levels of D-Dimer are an indication of active fibrinolysis and have been shown in patients with disseminated intravascular coagulation (DIC), deep vein thrombosis (DVT) and pulmonary embolism (PE). Elevated levels of D-Dimer have also been reported in surgery, trauma, sickle cell disease, liver disease, severe infection, sepsis, inflammation, malignancy and in the elderly. D-Dimer levels also rise during normal pregnancy but very high levels are associated with complications.
