D Dimer

Keywords: FDP, Fibrinogen degredation products

Specimen:

2 mL blood in EDTA or an appropriately collected citrate blood tube.

Method:

A number of methods that employ a monoclonal antibody specific for the degradation products of fibrin which has been crosslinked by Factor XIII are in use.

The techniques vary greatly in their sensitivity from semi-quantitative latex techniques to very sensitive ELISA based assays.

Results are usually issued as D Dimer, and this has largely replaced the previous less specific test for fibrin/fibrinogen degradation products (FDPs) in serum.

Reference Interval:

Check with laboratory.

Application:

Elevated D Dimer indicates recent or ongoing fibrinolysis, and the assay is used in the investigation of suspected disseminated intravascular coagulation (DIC) and for investigation of venous thrombosis in patients with a low prior probability based on standard clinical assessment.

Interpretation:

Levels of the traditional macro D Dimer test are usually increased in DIC, but moderate increases may be seen in patients with malignancy or severe infection.

This test is not recommended for the diagnosis of venous thromboembolism. However, a negative result of the sensitive D Dimer test in a non-hospitalised patient with a low pre-test probability is useful to exclude deep venous thrombosis as part of a defined clinical management algorithm.

D Dimer levels are also elevated in a number of other clinical settings including post surgery, disseminated intravascular coagulation (DIC), malignancy and inflammation. 

Reference:

Hirsch J, Lee A. Blood. 2002, 99: 3102-3110.

Wells et al. N Engl J Med. 2003, 349: 1227-1235

Bates et al. Chest. 2012, 141(2 Suppl): e351S-e418S.