Warfarin Sensitivity DNA Test

What is your safe and effective Warfarin dose?

  • Warfarin is a very effective drug to prevent abnormal blood clotting
  • Too much warfarin can lead to abnormal bleeding and not enough will fail to prevent abnormal blood clotting
  • Genetic variations affect the amount of warfarin that is required for a safe and effective dose
  • Simple mouth swab DNA test with results in 1 – 2 weeks
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What is the Warfarin Dose Genotyping Analysis?

The genes most commonly associated with the amount of warfarin required to obtain the required safe and effective blood anticoagulation level include CYP2C9, VKORC1, CYP4F2 and GGCX. The Warfarin Dose Genotyping Analysis DNA test panel includes the analysis of mutations in all four genes:

  • CYP2C9
  • VKORC1
  • CYP4F2
  • GGCX

The results of this analysis can significantly reduce the time taken to achieve a safe and stable level of blood anticoagulation, and may reduce the risks of potentially life-threatening problems.


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The kit can be ordered online, by fax or mail, or by phone. Once you place the order, the testing kit will be shipped directly to you. The kit contains swabs called “buccal swabs”. DNA is collected quickly and easily by rubbing the swabs inside your mouth against the cheek for 30 seconds. Once the DNA is collected, the swabs are placed into the specimen container provided in the kit and returned to the laboratory for testing using the return package included in the testing kit. Once your samples arrive at the laboratory, testing begins immediately and results are available in 1 to 2 weeks.

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Warfarin Side Effects

Warfarin Side Effects

Warfarin, especially if taken incorrectly, increases your risk of dangerous bleeding. Warfarin side effects can also include interactions with some foods, prescription medicines and over-the-counter supplements. Side effects can include:

  • Bleeding from the gums after you brush your teeth
  • Swelling or pain at an injection site
  • Heavier than normal menstrual bleeding or bleeding between menstrual periods
  • Diarrhea, vomiting or inability to eat for more than 24 hours
  • Fever

Serious Warfarin Side Effects

Warfarin activity and the resulting blood anticoagulation level is monitored is by blood testing of the patient to determine the international normalized ratio (INR). If the INR is too high, there is an increased risk of abnormal bleeding (hemorrhage). If the INR is too low, it indicates that it is insufficient to protect against blood clots (thrombosis). Serious warfarin side effects include:

  • Severe bleeding, including heavier than normal menstrual bleeding
  • Red or brown urine
  • Black or bloody stool
  • Severe headache or stomach pain
  • Joint pain, discomfort or swelling, especially after an injury
  • Vomiting of blood or material that looks like coffee grounds
  • Bruising that develops without an injury you remember
  • Dizziness or weakness

Frequently Asked Questions

Avada Admin

The Drug

What is warfarin? What are the risks of taking warfarin? What factors affect the dosing of warfarin?

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Avada Admin

The Test

What is the warfarin dose genotype analysis? Which genes are tested? How do genetic variations lead to adverse reactions?

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The Results

How will I receive my results? How long will testing take? What are the possible results and what are the interpretations for each result type?

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Get Started


Are you ready to get started? Print out this form and take it to your next doctor’s appointment to initiate a conversation with your doctor about Horizon carrier screening.

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Warfarin Learning Center

What factors affect Warfarin dosage?

International Normalized Ratio (INR) is a blood test used to determine the correct dose of warfarin, and monitor its anticoagulant effects. The higher the INR, the longer time it will take to clot, leading to [...]

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