• None

Blue (Preferred), Green or Purple top tube.

4-5 mL of venous blood.

If specimen is CSF; send immediately to lab in plastic CSF tube.

D-Dimer is a fibrin degradation product that is produced when formed clot is being broken down (fibrinolysis).

The clinical utility of the D-Dimer test is most commonly in risk stratification for Pulmonary Embolus (PE), Deep Venous Thrombosis (DVT) or Disseminated Intravascular Coagulation (DIC).

Note that a normal result is reassuring for the absence of PE, DVT or DIC, but an abnormal value is non-specific.

The ELISA D-Dimer (NOT the Latex Agglutination method) is commonly used for screening of low risk patients for potential PE. A normal value is reassuring for the absence of PE. This test is however not sufficiently reliable to exclude PE in cases where PE is of moderate or high clinical suspicion.

CSF may also be sent for D-Dimer to differentiate subarachnoid hemorrhage (Positive D-Dimer) from traumatic LP (Negative D-Dimer).

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

Quantitative (ELISA/Immunoturbidimetric):

• Normal < 500 mcg/L (< 500 ng/mL)

Some laboratories specify normal as < 250 mcg/L (< 250 ng/mL); however, for the purpose of evaluation for PE, typically 500 mcg/L is the upper limit of normal.

Note: Some assays use different normal ranges, consult your laboratory.

Latex Agglutination:

• Normal < 0.5 mcg/mL
• Borderline: 0.5-1.0 mcg/mL
• Increased: > 1.0 mcg/mL

Increased D-Dimer will occur in the following conditions:

• Pulmonary Embolus
• Deep Venous Thrombosis
• Disseminated Intravascular Coagulation
• Infections
• Arterial thrombosis
• Malignancy
• Pregnancy (late in pregnancy and in postpartum period)
• Pre-eclampsia
• Recent surgery
• Inflammatory disease
• Burns
• Trauma
• Acute MI or thrombotic stroke
• Possibly in renal or hepatic failure
• Will also increase after thrombolytic administration

N/A

• Brotman, DJ. Limitations of D-dimer testing in unselected inpatients with suspected venous thromboembolism. Am J Med 01 Mar 2003;114(4): 276-82.
• Caine, GJ. Validity of D-dimer tests for pulmonary embolism: better to diagnose or exclude? Ann Emerg Med 01 May 2003;41(5):756-7.
• http://www.emedicine.com/emerg/topic490.htm
• Rathbun, S, et al. D-dimer in the Diagnostic Workup of Suspected Pulmonary Embolism Additional Clinical Value of Pretest Probability. Chest Apr 2005;127(4).
• Stalnikowicz, R. Computed tomographic pulmonary angiography and D-dimer testing for pulmonary embolism: time for reappraisal. Am J Emerg Med 01 Mar 2006;24(2):252-3.