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Anticoagulation DNA Panel Blood Test

Last updated May 11, 2019

Approved by: Maulik P. Purohit MD, MPH

The Anticoagulant DNA Panel Blood Test detects variations in the CYP2C9 and VKORC1 genes. (Note: Gene variants are called alleles.) It increases the accuracy and ease of warfarin therapy by optimizing dosing.

What are other Names for this Test? (Equivalent Terms)

  • Anticoagulation Genetics Panel Blood Test

What is the Anticoagulation DNA Panel Blood Test? (Background Information)

  • Anticoagulant medications prevent the formation of blood clots. They are commonly called “blood thinners.” However, anticoagulant medications do not actually affect the thickness of blood
  • The most commonly prescribed anticoagulant medication is warfarin. It is also known as Coumadin, among other trade names
  • Warfarin works by halting the production of clotting factors. Clotting factors are proteins that help form blood clots at the site of blood vessel injury. Blood clots stop blood loss and allow the blood vessel to continue functioning
  • Injury to a blood vessel causes the blood vessel to constrict. Called the vascular phase, this is the first reaction of a blood vessel to damage. It reduces the flow of blood to the site of injury, minimizing blood loss
  • Next, circulating platelets clump along the site of blood vessel injury. Platelets form a foundation for a blood clot and release chemicals that stimulate clotting
  • The coagulation phase then causes a blood clot to form. Clotting occurs when an enzyme called thrombin converts a soluble protein, fibrinogen, into its insoluble form, fibrin. Fibrin proteins make up the bulk of a blood clot
  • Thrombin is activated by the merging of two pathways, the intrinsic and extrinsic pathways, into the common pathway. These are initiated by different parts of the body after blood vessel damage:
    • The intrinsic pathway begins in blood with the activation of circulating proteins;
    • The extrinsic pathway begins in the blood vessel with the release of protein factors by damaged cells lining the vessel
  • The extrinsic pathway is the first to activate. The intrinsic pathway then reinforces the extrinsic pathway and provides longer-lasting clotting effects. Coagulation factors are central to the action of these pathways. Each factor activates the next in a stepwise fashion
  • Once a coagulation factor is activated, it remains active. Thus, with each step in the pathway, more and more factors are activated. This results in a cascade of events similar to a snowball effect
  • A counter pathway ensures that the size of the growing blood clot stays in check. Problems with this regulatory pathway may lead to a dangerous condition where a blood clot forms within blood vessels (thrombosis)
  • Vitamin K is necessary for the formation of coagulation factors II, VII, IX, and X. These factors span across all three coagulation pathways. Warfarin interferes with the necessary enzymes’ abilities to use vitamin K and make these clotting factors
  • The instructions for producing those enzymes are encoded on the genetic blueprint. Two genes, CYP2C9 and VKORC1, are particularly susceptible to variations that result in enzymes with altered functional capacity and hence altered warfarin response
  • The Anticoagulant DNA Panel Blood Test detects variations in the CYP2C9 and VKORC1 genes. (Note: Gene variants are called alleles.) It increases the accuracy and ease of warfarin therapy by optimizing dosing

What are the Clinical Indications for performing the Anticoagulation DNA Panel Blood Test?

The Anticoagulation DNA Panel Blood Test is performed prior to warfarin therapy. It identifies genetic variations that may influence warfarin dosing.

How is the Specimen Collected for the Anticoagulation DNA Panel Blood Test?

Following is the specimen collection process for Anticoagulation DNA Panel Blood Test:

Sample required: Blood

Process of obtaining blood sample in adults:

  • A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
  • The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
  • The needle cap is removed and is held in line with the vein, pulling the skin tight
  • With a small and quick thrust, the vein is penetrated using the needle
  • The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
  • The wrap band is removed, gauze is placed on the collection site, and the needle is removed
  • The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
  • The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the Anticoagulation DNA Panel Blood Test Result?

Variations in the CYP2C9 and VKORC1 genes may indicate that the warfarin dose needs to be adjusted to reflect the individual’s personal genetic predispositions.

The following gene variants are detected:

  • For CYP2C9:
    • *2 (430C>T; Arg144Cys)
    • *3 (1075A>C; Ile359Leu)
  • For VKORC1
    • *2 (-1639G>A)

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • Certain factors may interfere with the Anticoagulation DNA Panel Blood Test. These include blood transfusions, DNA rearrangements, and bone marrow transplants

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

The following DoveMed website links are some useful resources for additional information:







Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 31, 2015
Last updated: May 11, 2019