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Test ID LBOR0204 Warfarin PharmGx Panel (4 Gene)

Important Note

This test is rarely covered by insurance.  A Patient Acknowledgement Form for Warfarin Response is required to accompany the specimen for all Medicare and non-Medicare patients. In the absence of the appropriate signed form, the ordering provider/facility will be billed.

For patients with Blue Cross Blue Shield of North Dakota Coverage, a separate completed and signed Advance Member Notice is required to accompany the specimen.

Note:  Testing results may be delayed due to nation-wide supply challenges due to the COVID pandemic.  Current expected TAT is 7-10 days.  

Specimen Type/Requirements

Lavender top (EDTA) tube - Whole Blood


Blood samples will not be accepted for patients that have undergone an allogenic transplant (e.g. bone marrow or peripheral stem cell) OR that have a history of chronic lymphocytic leukemia (CLL).


Transfusion patients: Wait at least 2 weeks after a packed cell/platelet transfusion, and at least 4 weeks after a whole blood transfusion prior to blood draw for testing.


Chemotherapy patients:  DNA quality may be affected if patient has received a chemotherapy within the last 120 days.  Clients will be contacted to provide additional specimen if DNA quality is insufficient.


All specimens should be sent in the original container and should not be aliquoted to another tube.  In addition, the specimen submitted should ONLY be used for this testing and should not be shared with any other testing that would also utilize this specimen type.


Testing is not affected by hemolysis or lipemia.


 Room Temperature     72 hours     
 Refrigerated     7 days     Preferred for transport   
 Frozen     Not Acceptable     



Allele-specific PCR

Performing Lab

Sanford Laboratories Sioux Falls

Performed Test Frequency

Monday through Friday



Report Available

5 - 7  days

Additional Information

The following 4 genes are included in this panel:

  • CYP2C9
  • VKORC1
  • CYP4F2
  • CYP2C Cluster 

See Pharmacogenomics Testing for Warfarin Metabolism for additional information.

Useful For

  • Identify genotypes shown to have a drug-gene variant relationship.



Specimen Volume

 Preferred Volume     2.0 - 4.0  mL   
 Minimum Volume     1.0 mL