Days Set Up
Monday - Friday
Analytic Time

3 - 12 days

Soft Order Code

Test Updated:


Warfarin Sensitivity Analysis
Cytochrome P450 2C9 Genotyping
Vitamin K Epoxide Reductase C1 Genotyping
CYP450 Genotype
VKORC1 Genotype
CYP2C9 Genotype

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Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

Visit our provider FAQ and learn about common questions to ordering tests.

Test Overview

Test Methodology

Real-Time Polymerase Chain Reaction (PCR) with Allelic Discrimination Analysis

Test Usage

This test is used for identifying patients who may require warfarin (Coumadin) dosing adjustments including: patients who are receiving warfarin for the first time; patients who have required multiple dosing adjustments to maintain the international normalized ratio (INR) in the target range; and patients with a history of thrombosis or bleeding when taking warfarin.

Reference Range

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect specimen in a lavender top (EDTA) tube. Send intact specimen at room temperature within 24 hours of collection

Lavender Top Tube
Normal Volume
3 mL EDTA whole blood
Minimum Volume
0.5 mL EDTA whole blood

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.