Ordering Recommendation

Use to identify individuals with inherited gene variants that affect dose requirements for warfarin.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature


Unacceptable Conditions

Plasma or serum. Specimens collected in sodium heparin or lithium heparin. Frozen specimens in glass collection tubes.


Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month


Polymerase Chain Reaction (PCR)/Fluorescence Monitoring




5-10 days

Reference Interval

By report

Interpretive Data

Refer to report

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Couseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Laboratory Developed Test (LDT)


Whole blood is the preferred specimen. Saliva samples that yield inadequate DNA quality and/or quantity will be reported as inconclusive if test performance does not meet laboratory-determined criteria for reporting.

Hotline History


CPT Codes

81227; 81355; 81479


Component Test Code* Component Chart Name LOINC
2008931 CYP2C9 Phenotype 79716-7
3001504 CYP2C9 Genotype 46724-1
3001542 WARF PAN Specimen 31208-2
3001543 CYP4F2 Genotype 93197-2
3001544 VKORC1 Genotype 101590-8
3001545 WARF PAN Interpretation 50398-7
3004499 CYP2C Cluster Geno 101785-4
3004500 CYP2C Cluster Pheno 81259-4
3004506 CYP4F2 Phenotype 81259-4
3004507 VKORC1 Phenotype 81259-4
3016870 EER Warfarin Sensitivity Genotyping 11526-1
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Coumadin
  • CYP2C cluster
  • CYP2C9
  • CYP4F2
  • VKORC1
  • warfarin
Warfarin Sensitivity (CYP2C9, CYP2C cluster, CYP4F2, VKORC1) Genotyping