A thrombophilia screen is a group of tests used to determine if a person has an inherited or acquired risk for developing abnormal blood clots (thrombosis). The exact tests included in a thrombophilia screen may vary based on clinical and laboratory protocols, but generally, the following tests are considered:
- Inherited Thrombophilias:
- Factor V Leiden mutation: This is the most common inherited thrombophilia in individuals of European descent. Individuals who have this mutation are at increased risk for deep vein thrombosis (DVT).
- Prothrombin gene mutation (G20210A): This is the second most common inherited thrombophilia.
- Antithrombin III activity: Deficiency in antithrombin can lead to an increased risk of thrombosis.
- Protein C activity: Deficiency in protein C can increase thrombotic risk.
- Protein S activity: Deficiency in protein S can also lead to an increased risk of thrombosis.
- Acquired Thrombophilias (Anti-phospholipid syndrome):
- Lupus anticoagulant: It’s part of the antiphospholipid antibody syndrome (APS) testing.
- Anticardiolipin antibodies (IgG, IgM, and sometimes IgA): Also part of APS testing.
- Anti-β2 glycoprotein I antibodies: Another component of APS testing.
- Other Tests That Might Be Included or Indicated Based on Clinical Context:
- Homocysteine levels: Elevated levels can be due to inherited conditions (e.g., MTHFR gene mutations) or acquired conditions (e.g., vitamin B12 or folate deficiency) and can increase the risk of thrombosis.
- Fibrinogen level: Elevated fibrinogen can increase the risk of thrombosis.
Before conducting a thrombophilia screen, it’s crucial to evaluate the clinical appropriateness.
Under the MBS criteria, FHx or DVT must be flagged for tests to be subsidised.
Testing during an acute thrombotic event or while on anticoagulation may yield inaccurate results.