CYP2C19 Genotype (Cytochrome p450 2C19) for Drug Metabolism
Epic order code: LAB5169
- EDTA: Lavender-top tube;
- K2EDTA: Pink-top tube; or
- ACD Solution A or B: Yellow-top tube.
Severely hemolyzed, clotted and/or frozen blood specimens, and specimens in heparin (green-top) tubes are not accepted.
Specimen Preparation: Transport 3 mL of whole blood. (minimum 1 mL)
Storage/Transport Temperature: Refrigerated
- Ambient: 72 hours
- Refrigerated: 1 week
- Frozen: Unacceptable
This test identifies the CYP2C19 genotype to determine the patient's rate of metabolism for drugs activated or inactivated by this pathway. It has particular importance in metabolizing the drug clopidogrel (Plavix®).
Real-time polymerase chain reaction-based/fluorescence-monitoring test
No allelic variants detected (*1/*1)
Monday - Friday
Analytical Interpretation: The report includes the patient's diplotype of CYP2C19 genes and is reported using star alleles as follows:
- *1/*1 for no allelic variant present; or
- *17/*17 for a homozygous c.991A>G genotype (which has increased function).
|CYP2C19 Allelic Variants Tested|
|Allele||Nucleotide||Effect||Predicted Enzyme Activity|
|*1||No allelic variant||Normal||Normal|
|*3||c.636G>A||New stop codon||Non-functional|
|*4||c.1A>G||Loss of initiation||Non-functional|
|*17||c.991A>G||Increased transcription||Increased function|
- Normal metabolism
- Impaired metabolism
- Very imparied metabolism
- Enhanced metabolism
- Unknown effect on metabolism
- Indeterminate result