Thrombophilia Screen

OVERVIEW

• Thrombophilia is a predisposition to increased risk of venous and arterial thromboembolism due to haemostatic abnormalities
• It may be multifactorial, with hereditary defects of anticoagulant or procoagulant factors potentially acting in concert with acquired hematological abnormalities
• Thrombophilia screening should be considered in patients with a documented unexplained thrombotic episode or a positive family history

TESTS

• Factor V Leiden mutation
• Prothombin gene mutation
• Hyperhomocysteinemia (fasting)
• Antiphospholipid antibody syndrome (lupus anticoagulant and anticardiolipin antibodies)
• Deficiency of antithrombin III, protein C or protein S
• High concentrations of factor VIII or XI
• Increased lipoprotein (a)

ANTITHROMBIN III DEFICIENCY

Causes

• Hereditary, or Acquired:
• Post-operative state
• Liver disease
• Disseminated intravascular coagulation
• Nephrotic syndrome
• Vasculitis

Types

• I = decreased ATIII activity and immunoreactivity
• II = decreased ATIII activity, but normal antigen levels

Investigations

• ATIII activity on blood sample
• Thrombophilia screen

Management

• IV heparin
  • If there is heparin resistance or low ATIII activity, either antithrombin III concentrate or FFP can be used
• monitor ATIII activity

 References and Links

Journal articles

• Merriman L, Greaves M. Testing for thrombophilia: an evidence-based approach. Postgrad Med J. 2006;82:(973)699-704. [PMID 17099087]
• Rhodes EG. Thrombophilia and the surgeon. Ann R Coll Surg Engl. 1996;78:(4)331-5. [PMID 8712645]
• Tripodi A, Mannucci PM. Laboratory investigation of thrombophilia. Clin Chem. 2001;47:(9)1597-606. [PMID 11514392]