Testing & Diagnosis
Thrombophilia Tests: When and For Whom Are They Necessary?
Genetic testing is not needed in every thrombosis case. Correct timing, patient selection and interpretation of the thrombophilia panel.
7 min · 20 April 2025
Thrombophilia testing is not routine screening for everyone; it adds value in the right patient, at the right time, with the right indication. This article covers panel contents, test timing and result interpretation.
What Is in the Panel?
Our standard thrombophilia panel includes:
- Genetic analysis (PCR): Factor V Leiden (G1691A), Prothrombin G20210A, MTHFR C677T and A1298C variants.
- Functional activity assays: Protein C, Protein S and Antithrombin III activities.
- Optional: Homocysteine and antiphospholipid antibody panel (per clinical suspicion).
Who Should Be Tested?
- DVT or pulmonary embolism under 45 without an obvious trigger.
- Recurrent pregnancy loss (especially after 10 weeks) or severe preeclampsia.
- Thrombosis in unusual sites: mesenteric, hepatic or cerebral veins.
- Multiple family members with early thrombosis.
- Families with neonatal purpura fulminans history (for Protein C/S deficiency).
Why Test Timing Matters?
Protein C, S and antithrombin levels change naturally during acute thrombosis and under anticoagulants; results in those periods can mislead. Therefore:
- Functional assays should be drawn at least 4-6 weeks after the acute event, ideally during an anticoagulant-free interval.
- Warfarin lowers Protein C/S; LMWH and rivaroxaban can also complicate interpretation. Planning is done with your physician.
- Genetic tests (FVL, PT, MTHFR) are always reliable — unaffected by medication or event timing.
How Are Results Interpreted?
- Heterozygous FVL or PT: Mild-moderate risk increase; individualized plan by history.
- Homozygous FVL/PT or combined mutations: High risk; aggressive prevention and family screening.
- Protein C/S or Antithrombin deficiency: Higher risk; lifelong prophylaxis may be considered in some.
- Negative panel: Does not exclude risk; acquired causes and antiphospholipid syndrome are evaluated separately.
The meaning of a result is always weighed against personal thrombosis history, family history and additional risk factors. A "positive gene" alone does not mean treatment; a "negative gene" does not mean absence of risk.
Preparation
No special preparation is needed for genetic analysis; fasting is not required. For Protein C/S and antithrombin assays, medication timing matters. The blood draw takes under five minutes from an arm vein.
Conclusion
The thrombophilia panel strengthens risk prediction and prevention planning in the right patient. Specialist guidance is essential for indication, timing and interpretation. Our laboratory delivers a personalized report together with your clinical team.