Skip to content

: VKORC1 Gene Allele Genotyping, Whole Blood

Published: August 9, 2026Updated: August 16, 2026

: This test examines the VKORC1 gene from a whole blood sample to identify common genetic variants that can influence how a person responds to the blood thinner warfarin.

Quick summary

: VKORC1 genotyping can help explain individual differences in warfarin sensitivity, but results are interpreted alongside other clinical factors.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
101590-8
Short code
VKORC1 gene allele Geno Bld/T
Synonyms
VKORC1 gene allele Geno Bld/T
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

: What This Test Looks At

: The VKORC1 gene provides instructions for making an enzyme that warfarin targets to prevent blood clotting. Certain common variations in this gene can make a person more or less sensitive to warfarin, which may affect the dose needed to achieve a safe and effective effect.

: How the Sample Is Collected

: A small whole blood sample is collected, usually from a vein in the arm. The DNA is then analyzed in the laboratory to determine which VKORC1 variants are present.

: What the Results Mean

: Results describe which VKORC1 variants were detected. Some variants are linked to increased warfarin sensitivity, while others are linked to more typical sensitivity. Your care team uses this information together with clinical factors to guide dosing decisions.

: Important Limitations

: VKORC1 genotype is only one piece of the puzzle. Age, weight, diet, other medications, and additional genetic factors such as CYP2C9 variants also affect warfarin response. This test does not by itself determine a warfarin dose, and it should not replace regular blood monitoring.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

: VKORC1 genotyping is used to support personalized warfarin dosing and to help identify people who may be more sensitive to the drug. It is most useful when combined with other clinical and genetic information and with ongoing monitoring of clotting status.

Short name

: VKORC1 Genotype

Frequently asked questions

: Does this test tell me my exact warfarin dose?
: No. It provides genetic information that your care team considers alongside other factors, and dosing is adjusted based on your individual response and monitoring.
: Is a blood draw required?
: Yes. The test uses a whole blood sample, typically collected from a vein.
: Can the result change over time?
: No. Your inherited VKORC1 variants do not change, so a result generally stays the same for life.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy