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CYP2C19 Genotype

Published: July 27, 2026Updated: August 25, 2026

The CYP2C19 genotype test determines variations in the CYP2C19 gene, which affects how certain drugs, such as clopidogrel, are metabolized in the body.

Quick summary

CYP2C19 genotype predicts response to medications metabolized by the CYP2C19 enzyme.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
genotype
Clinical utility
predictive
Result kind
qualitative
FDA-cleared
Roche AmpliChip CYP450, Abbott Infiniti CYP2C19, AutoGenomics CYP2C19, Spartan RX CYP2C19
interpretation: {"text":"Individuals with the 0–0 genotype are classified as poor metabolizers, meaning they have little to no CYP2C19 enzyme activity and may require dose adjustments or alternative medications.","label":"0–0 genotype"}; {"text":"Different genotypes result in varying levels of enzyme activity, influencing drug metabolism and potential need for dose or drug changes.","label":"Other genotypes"}

The CYP2C19 gene encodes an enzyme that plays a crucial role in the metabolism of several drugs, including some antidepressants, antiplatelet agents, and proton pump inhibitors.

Variations in the CYP2C19 gene can lead to different phenotypes, such as poor metabolizers, intermediate metabolizers, extensive metabolizers, and ultra-rapid metabolizers.

Understanding a patient's CYP2C19 genotype can help clinicians tailor drug dosages or choose alternative medications to optimize therapeutic outcomes and minimize adverse effects.

Frequently asked questions

What is the clinical significance of CYP2C19 genotyping?
CYP2C19 genotyping helps in personalizing drug therapy by predicting how an individual will metabolize certain medications, thereby reducing the risk of treatment failure or adverse effects.
How is the CYP2C19 genotype test performed?
The test is typically performed using a blood or saliva sample, with DNA analysis to identify specific genetic variations in the CYP2C19 gene.
  1. 1
    CYP2C19 Genotype and Clopidogrel Response: 2013 UpdateSource
  2. 2
    Pharmacogenomics Knowledge Base (PharmGKB): CYP2C19Source

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 25, 2026. · Read our editorial policy