D-dimer test

By far the most widely measured marker of hemostatic activation is D-dimer, which is a product formed by the action of plasmin on cross-linked fibrin (95). D-dimer levels in plasma are generally elevated in DIC. The consumption of platelets and coagulation proteins as a result of thrombin generation leads to the deposition of fibrin thrombi at multiple organ sites. This triggers fibrinolysis with an increase in the formation of fibrin degradation products, which can cause bleeding at multiple sites. Because DIC can have a variety of causes and may coexist with systemic fibrinolysis, such as in pulmonary embolism or deep vein thrombosis, the d-Dimer test is not specific for DIC (95). 

D-dimer is a degradation product of fibrin blood clots, and levels obtained by a simple blood test are substantially elevated in patients with acute thrombosis. Although the D-dimer test is a very sensitive marker of clot formation, elevated levels can result from a variety of other conditions (e.g., recent surgery or trauma, pregnancy, and cancer). Therefore, a negative test can help exclude the diagnosis of VTE, but a positive test cannot confirm the diagnosis. 

Coomb s test direct indirect D-Dimer test... 

Plasmin cleaves fibrin at different positions. Of high clinically practical relevance is the cleavage of the fibrin y-chain that results in D-Dimers (Fig. 11). D-Dimers are specific for fibrin cleavage by plasmin. They can easily be detected by commercially available assays and are used to exclude thrombosis. A negative test for D-Dimer has a high negative predictive value for a thrombosis. 

D-dimer this test may be a helpful adjunct to either a venous ultrasound or V/Q scan... 

The use of ELISA is broad and it finds applications in many biological laboratories over the last 30 years many tests have been developed and vahdated in different domains such as clinical diagnostics, pharmaceutical research, industrial control or food and feed analytics for instance. Our work has been to redesign the standard ELISA test to fit in a microfluidic system with disposable electrochemical chips. Many applications are foreseen since the biochemical reagents are directly amenable from a conventional microtitre plate to our microfluidic system. For instance, in the last 5 years, we have reported previous works with this concept of microchannel ELISA for the detection of thromboembolic event marker (D-Dimer) [4], hormones (TSH) [18], or vitamin (folic acid) [24], It is expected that similar technical developments in the future may broaden the use of electroanalytical chemistry in the field of clinical tests as has been the case for glucose monitoring. This work also contributes to the novel analytical trend to reduce the volume and time consumption in analytical labs using lab-on-a-chip devices. Not only can an electrophoretic-driven system benefit from the miniaturisation but also affinity assays and in particularly immunoassays with electrochemical detection. 

Mooij, G. C. and Frenkel, D., Numerical test of the generalized Flory and generalized Flory dimer theories. J. Chem. Phys. 100, 6088-6091 (1994). 

Factor Vlll and V levels should be decreased in DlC, but results of these tests may be quite variable because of the systemic activation of the coagulation system. The most specific findings of DlC are a low platelet count associated with an elevated D-dimer level, fibrinopeptide A, and prothrombin 1 and 2, along with depressed antithrombin and fibrinogen levels. 

Sidelmann JJ, Gram J, Larsen A, Overgaard K, Jespersen J. Analytical and clinical validation of a new point-of-care testing system for determination of D-Dimer in human blood. Thromb Res 2010 126 524-30. 

The PE has to be large to show up on the ECG. A small PE may not show up on the ECG at all. The ECG should be used as a guide to diagnosis only. PE diagnosis is usually confirmed by bloods tests showing a raised D-dimer and subsequent CTPA (CT Pulmonary Angiography). 

Failure of sensitive filtration tests such as ASTM D-2276, Particulate Contamination in Aviation Fuel by Line Sampling, can be due to caustic neutralized corrosion inhibitor salts. Sodium or calcium salts of dimer-trimer fatty acid corrosion inhibitors are gel-like in character. Filtration of jet fuel containing gelled corrosion inhibitor will be impeded due to plugging of fuel filter media by the inhibitor gel. This slowdown of filtration can result in failure of jet fuel to pass this critical performance test. 

Recent ab initio calculations have attempted to probe the fundamental source of the reversal of H/D preference in ionic as compared to neutral systems, using water as a test base. A harmonic analysis of the potential energy surface of the water dimer, computed with a 6-31G basis set, indicates that the preference for D in the bridging site can be explained in a manner similar to that described earlier for HF - HF. The frequency of the bending motion of the bridging atom is sensitive to its mass this effect leads to a lower vibrational energy of some 0.2 kcal/mol when the heavier D undergoes this motion. The computations indicated that electron correlation has little effect upon this conclusion, even its quantitative aspects. While the treatment was purely harmonic in nature, other calculations have indicated that anharmonicity effects yield very little distinction between one isotopomer and the next. 

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