1. Prior history of DVT, VTE or PE.  (deep venous thrombosus, venous thromboembolism, or pulmonary embolus)

2. Malignancy (active or in a patient’s history)

3. Thrombophilia disorders.*

4. Obesity (particularly for obese patients <40 years of age)

5. Use of oral contraceptives, tamoxifen, hormone replacement therapy or estrogen-containing drugs.

*Inherited and acquired Thrombophilia disorders include:

Factor V Leiden mutation

Prothrombin 20210A mutation (found only in whites)

Protein S deficiency

Protein C deficiency

High levels of: Fibrinogen, Plasminogen, Factor VIII, Factor IX, Thrombin activatable fibrinolysis inhibitor or Protein C inhibitor.

Low levels of tissue factor pathway inhibitor (TFPI)

Hyperhomocysteinemia (plasma homocysteine level >18.5 mmol/L)

Antiphospholipid antibodies (lupus anticoagulant & anti-cardiolipin)