D-Dimer

Coagulation

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Description

Coagulation activation results in the cleavage of fibrinogen to fibrin monomer.The fibrin monomers spontaneously aggregate to fibrin and are crosslinked by the action of Factor XIII to produce a stabilised fibrin clot. In response to the coagulation process the fibrinolytic system is activated resulting in the conversion of plasminogen to plasmin, which cleaves fibrin (and fibrinogen)into the fragments D and E. Due to cross-linkage between D-domains in the fibrin clot, the action of plasmin releases fibrin degradation products with cross-linked D-domains. The smallest unit is D-dimer. Detection of D-dimers, which specifies cross-linked fibrin degradation products generated by reactive fibrinolysis, is an indicator of coagulation activity.

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Indications

Negative predictive value when used as part of Trust protocol for exclusion of VTE.

Can be used as an indirect assay of fibrin generation in DIC investigation.

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Sample Type

Plasma (Citrate 2.7ml Blue) x 1

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Reference Range

Reference Range 0-500 ug/L
Cut-off for DVT/PE exclusion is <500ug/L when using Trust protocol for patients not on anticoagulants.

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Turnaround Time

Within 1 hour

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Testing Frequency

Daily/continuous processing 24hrs.

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External Notes

The accuracy of all coagulation tests is greatly influenced by pre analytical variables. It is essential that sample quality is given the highest of priorities. Samples which fail to meet quality criteria including age of sample, specimen fill (>90%), haemolysed, clotted or activated samples will be rejected and a repeat sample requested.

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References

1.CLSI. Collection, Transport and Processing of Blood Specimensfor Testing Plasma-based Coagulation Assays and Molecular Haemostasis Assays. Approved Guideline - Fith Edition. CLSI document H21-a5 [ISBN 1-56238-657-3]. CLSI, 940 West Valley Rd., Suite 1400 Wayne, Pennsylvania 19087-1898 USA, 20082.Francis CW, Marder VJ. A model of plasmic degradation of cross-linked fibrin. Sem Thromb Hemost 1982;8:25-353.Wells PS. The role of qualitatine D-Dimer assays, clinical probability, and non invasive imaging tests for the diagnosis of DVT and PE. Semin Vasc Med 2005;5:340-3504.Wells PS, Anderson DR, Rodger M et al. Evaluation of D-Dimer in the diagnosis of suspected deep-vein thrombosis. N Eng J Med 2003;349:1227-35 5.ANDERSON DR et al (2003). COMBINED USE OF CLINICAL ASSESSMENT AND D-DIMER TO IMPROVE THE MANAGEMENT OF PATIENTS PRESENTING TO THE ER WITH SUSPECTED DVT. J THROMBOSIS HAEMOSTASIS. 1:645-51

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