CYP2C19 Genotype

CYP2C19 Genotyping for Clopidogrel/Plavix, Clopidogrel (Plavix), Cytochrome P450 2C19 Genotyping, Plavix (Clopidogrel), Treatment Resistant Depression Panel, Plavix Inhibition, CardioIQ®, CYP2C19 Genotype

Test Codes

EPIC: LAB1231987, Beaker: CYP2C19, Quest: 90668

Department

Send Outs

Specimen Collection Criteria

Collect: One Lavender-top EDTA tube.
Also acceptable: One Pink-top EDTA tube.

Physician Office/Draw Specimen Preparation

Do not centrifuge. Maintain whole blood refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Whole blood refrigerated (2-8°C or 36-46°F). (Minimum: 2.0 mL)

Rejection Criteria

• Specimens not collected and processed as indicated.
• This test will only be performed once in a lifetime for a patient.

In-Lab Processing

Do not centrifuge. Maintain whole blood refrigerated (2-8°C or 36-46°F) prior to transport.

Transport: Whole blood refrigerated (2-8°C or 36-46°F). (Minimum: 2.0 mL)

Storage

Specimen Stability for Testing:

Whole Blood
Room Temperature (20-26°C or 68-78.8°F): 8 days
Refrigerated (2-8°C or 36-46°F): 8 days
Frozen (-20°C/-4°F or below): 1 month

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Monday, Wednesday – Saturday.
Results available in 2-4 business days.

Reference Range

By Report.

Test Methodology

Allele-Specific Primer Extension, Polymerase Chain Reaction (PCR).

Clinical Utility

Cardio IQ® CYP2C19 Genotype – This pharmacogenetic test may be used to help guide clopidogrel prescribing, especially in patients with acute coronary syndrome (ACS) who have undergone percutaneous coronary intervention (PCI) [1]. This test detects common variants in the CYP2C19 gene, the most validated genetic determinant of clopidogrel response.

Clopidogrel is a prodrug that needs to be metabolized to its active form by cytochrome P450 2C19 (CYP2C19). Patients who carry a no-function allele of CYP2C19 have reduced clopidogrel activation, reduced platelet inhibition, and higher risk of major adverse cardiovascular events. Treatment outcomes may be improved in these patients with alternative antiplatelet therapies, such as prasugrel or ticagrelor. Therefore, CYP2C19 genotyping is helpful for assessing an individual's capability to metabolize clopidogrel and optimizing antiplatelet therapy [1].

CYP2C19 genotype classifies individuals as ultrarapid, rapid, normal, intermediate, likely poor, poor, and indeterminate metabolizers. The Clinical Pharmacogenetics Implementation Consortium (CPIC) provides guidelines for using CYP2C19 status to help direct clopidogrel prescribing. Although the association between CYP2C19 genotype and clopidogrel response is most established in patients with ACS who have undergone PCI, growing evidence indicates a similar association in patients with neurovascular indications [1]. The FDA boxed warning indicates diminished antiplatelet effect in CYP2C19 poor metabolizers and availability of tests to identify these individuals [2].

This is a targeted genotyping test and does not detect deletions or novel or rare variants of CYP2C19. CYP2C19 genotype does not identify all the variability in clopidogrel response. Other factors, such as age, body mass index, chronic kidney disease, diabetes mellitus, and concomitant use of certain proton pump inhibitors, may also influence clopidogrel response [1].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

Additional assistance in test selection and interpretation of results is available from our genomic science specialists by calling 1.866.GENE.INFO (1.866.436.3463).

Reference

1. Lee CR, et al. Clin Pharmacol Ther. 2022;10.1002/cpt.2526.
2. PLAVIX® (clopidogrel bisulfate). Prescribing information. Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership; 2019. Accessed March 5, 2022. https://packageinserts.bms.com/pi/pi_plavix.pdf

CPT Codes

81225

Contacts

Last Updated

11/19/2025