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F2 (Prothrombin) Variant and Blood Clot Risk: What Your Genotype Means

Blood clots are essential to stop bleeding after injury, but they can become harmful when they form inside blood vessels. The F2 gene makes prothrombin, a protein central to the clotting process. A common variant at rs1799963 can increase prothrombin levels and raise the chance of inappropriate clot formation, which may lead to deep vein thrombosis (DVT), pulmonary embolism (PE), or ischemic stroke. Genetics is one piece of the puzzle — lifestyle, medical conditions, and other genes also shape your overall risk.

How to read this result

  • AA — two copies of the effect allele. Elevated prothrombin production and higher genetic risk for clotting.
  • AG — one copy of the effect allele. Moderately increased genetic risk for clotting.
  • GG — no effect alleles. Typical risk from this gene variant.

Practical steps everyone can take

No matter your genotype, the following habits support healthy blood flow and lower overall clot risk:

  • Stay active: Aim for regular aerobic exercise (walking, cycling, swimming) and avoid long periods of immobility.
  • Maintain a heart-healthy diet: Emphasize fruits, vegetables, whole grains, lean proteins, and healthy fats.
  • Hydration: Drink enough fluids to avoid dehydration, which can thicken blood.
  • Avoid smoking and limit alcohol: Both can increase clot and cardiovascular risk.
  • Manage medical conditions: Keep blood pressure, cholesterol, diabetes, and weight under control with your provider’s guidance.
  • Know clot triggers: Prolonged travel, surgery, pregnancy, certain medications (including some hormonal therapies), and immobilization can increase risk.

Genetic Interpretation

AA — two effect alleles (higher genetic risk)

If your genotype is AA at rs1799963 you carry two copies of the effect allele. This is associated with higher prothrombin levels and a greater predisposition for blood clots such as deep vein thrombosis, pulmonary embolism, and ischemic stroke. This genetic finding means your blood may be more likely to form clots inappropriately, though it does not guarantee a clot will occur.

Recommended focus:

  • Medical follow up: Discuss this result with your healthcare provider or a hematologist to determine whether additional testing or monitoring is appropriate.
  • Medication review: Some people with a high clotting risk may need anticoagulation in specific situations (surgery, prolonged immobility, pregnancy). Only start or stop medications under medical supervision.
  • Pregnancy and contraception planning: If you are pregnant, planning pregnancy, or considering estrogen-containing birth control, talk with your provider about individualized risk and possible alternatives.
  • Emergency awareness: Learn signs of DVT (leg pain, swelling, redness), PE (sudden shortness of breath, chest pain), and stroke (sudden weakness, slurred speech). Seek immediate care if symptoms appear.
AG — one effect allele (moderately increased risk)

The AG genotype indicates one effect allele at rs1799963. This is associated with increased prothrombin production and a likely elevated risk of blood clots, including DVT, PE, and ischemic stroke. Your risk is higher than average but less than for two copies. This genetic factor interacts with lifestyle and other medical risks.

Recommended focus:

  • Discuss with your provider: Review family and personal history of clotting to decide whether further testing or lifestyle steps are needed.
  • Reduce modifiable risks: Prioritize movement during long travel, maintain hydration, avoid smoking, and control cardiovascular risk factors.
  • Medication and pregnancy planning: Review any hormones, certain drugs, or planned surgeries with your provider to assess whether temporary preventive measures are needed.
  • Monitoring: If you develop risk-enhancing conditions (immobility, injury, surgery, pregnancy), plan preventive strategies with your clinician.
GG — zero effect alleles (typical risk for this variant)

With the GG genotype you do not carry the F2 rs1799963 variant that increases prothrombin production. This indicates a typical inherited risk regarding this specific gene. It does not eliminate clot risk, since other genetic variants, medical conditions, and lifestyle factors also contribute.

Recommended focus:

  • Maintain preventative habits: Continue healthy lifestyle measures to minimize overall clot and cardiovascular risk.
  • Know other risks: If you have a family history of clotting or personal risk factors, discuss further genetic or clinical evaluation with your clinician.
  • Stay informed around events that raise clot risk: pregnancy, major surgery, prolonged immobility, and certain medications may still warrant preventive actions.

Diet and supplement considerations

Diet supports vascular health and can indirectly influence clot risk. Consider these practical tips and discuss supplements with your healthcare provider before starting them, especially because some can interact with blood-thinning medications.

  • Heart-healthy eating: Focus on colorful fruits and vegetables, whole grains, legumes, lean proteins, and nuts. Limit processed foods, excess salt, and refined sugars.
  • Omega-3 fatty acids: Found in oily fish and some supplements, omega-3s may support cardiovascular health. Use only under medical advice if you have a clotting disorder or take anticoagulants.
  • Vitamin K awareness: Leafy greens contain vitamin K, which affects some blood-thinning medicines. Maintain consistent intake and inform your clinician rather than avoiding these vegetables.
  • Avoid unproven "natural" clot dissolvers: Do not substitute herbs or supplements for medically recommended therapies without clinician approval.

Recommended blood tests and clinical follow-up

  • Talk to your clinician about targeted testing if you have a personal or family history of clots, including tests for other thrombophilia genes and coagulation studies.
  • Baseline cardiovascular screening: Measure blood pressure, fasting lipids, glucose or A1c, and body mass index to address modifiable risks.
  • Perioperative or pregnancy planning: Inform your surgical team or obstetric provider about your genotype so they can plan prophylaxis if needed.

When to seek immediate care

  • Signs of DVT: new leg swelling, pain, warmth, or redness.
  • Signs of PE: sudden shortness of breath, chest pain, rapid heart rate, or fainting.
  • Signs of stroke: sudden weakness or numbness on one side, confusion, trouble speaking, loss of vision, or severe headache.

PlexusDx provides education about genetic predispositions only and does not provide medical advice. This information is not a diagnosis. Always discuss genetic findings, testing options, and management strategies with a qualified healthcare provider before making medical decisions.