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Test Code WARSQ Warfarin Response Genotype, Varies


Ordering Guidance


If patient is using medications other than warfarin, the preferred test is 2C9QT / Cytochrome P450 2C9 Genotype, Varies, which tests for only the CYP2C9 gene.

 

Testing is available as the single gene assay (this test) or as a part of a focused pharmacogenomics panel, which includes testing for the following genes: CYPs 1A2, 2C9, 2C19, 2D6, 3A4, 3A5, 4F2, SLCO1B1, and VKORC1. Order PGXQP / Focused Pharmacogenomics Panel, Varies if multiple pharmacogenomic genotype testing is desired.



Specimen Required


Multiple genotype tests can be performed on a single specimen after a single extraction. See Multiple Genotype Test List in Special Instructions for a list of tests that can be ordered together.

 

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient (preferred) 9 days/Refrigerated 30 days

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Swab Collection Kit (T786)

Specimen Volume: 1 swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient 30 days

 

Specimen Type: Extracted DNA

Container/Tube: 2 mL screw top tube

Specimen Volume: 100 mcL (microliters)

Collection Instructions:

1. The preferred volume is 100 mcL at a concentration of 50 ng/mcL.

2. Include concentration and volume on tube.

Specimen Stability Information: Frozen (preferred)/Ambient/Refrigerated


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Neurology Specialty Testing Client Test Request (T732)

-Therapeutics Test Request (T831)

-Cardiovascular Test Request (T724)

Useful For

Identifying patients who may require warfarin dosing adjustments(3,4) including:

-Patients being started on a first prescription for warfarin

-Patients who have previously been prescribed warfarin and have required multiple dosing adjustments to maintain the international normalized ratio in the target range

-Patients with a history of thrombosis or bleeding when taking warfarin

Genetics Test Information

This test is used for assessing CYP2C9, VKORC1, CYP4F2, and rs12777823 for variants affecting the metabolism of warfarin (Coumadin). This assay should be ordered on patients who are receiving warfarin for the first time or who are experiencing difficulties in maintaining the international normalized ratio (INR) in the therapeutic range.

Reporting Name

Warfarin Response Genotype, V

Specimen Type

Varies

Specimen Minimum Volume

Blood: 0.4 mL
Saliva: 1 swab

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Friday

Report Available

3 to 10 days

Specimen Retention Time

Whole Blood/Saliva swab: 2 weeks; Extracted DNA: 2 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

0030U

LOINC Code Information

Test ID Test Order Name Order LOINC Value
WARSQ Warfarin Response Genotype, V 93196-4

 

Result ID Test Result Name Result LOINC Value
610175 Warfarin CYP2C9 Genotype 46724-1
610176 Warfarin VKORC1 Promoter Genotype 50722-8
610560 Warfarin CYP2C9 and VKORC1 Promoter Phenotype 54451-0
610177 Warfarin Resistance Variants 50722-8
614410 Warfarin VKORC1 Resistance Genotype 50722-8
610178 Warfarin CYP4F2 *3 Genotype 93197-2
610179 Warfarin rs12777823 Genotype 93198-0
610180 Interpretation 69047-9
610181 Additional Information 48767-8
610182 Method 85069-3
610183 Disclaimer 62364-5
610184 Reviewed by 18771-6