Assesses genetic risk of abnormal drug metabolism for CYP2C19 substrates. May aid in drug selection and dose planning for drugs metabolized by CYP2C19.
Polymerase Chain Reaction/Fluorescence Monitoring
Whole Blood: Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).
Saliva: Collection Device by DNA Genotek (OCD-100, ARUP Supply #49295) available online through eSupply using ARUP Connect™ or by contacting ARUP Client Services at (800) 522-2787.
Transport 3 mL whole blood. (Min: 1 mL) OR Transport the Saliva Collection Device.
Whole Blood: Refrigerated.
Saliva: Room temperature.
Plasma or serum. Specimens collected in sodium heparin or lithium heparin.
Whole Blood: Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month
Saliva: Ambient: 2 weeks; Refrigerated: Unacceptable; Frozen: Unacceptable
Background Information for CYP2C19:
Characteristics: The cytochrome P450 (CYP) isozyme 2C19 is involved in the metabolism of many drugs. Variants in the gene that code for CYP2C19 will influence pharmacokinetics of CYP2C19 substrates, and may predict or explain non-standard dose requirements, therapeutic failure or adverse reactions.
Inheritance: Autosomal codominant.
Cause: CYP2C19 gene variants affect enzyme expression or activity.
Variants Tested: See the Additional Technical Information document.
Clinical Sensitivity: Drug-dependent.
Methodology: Polymerase chain reaction (PCR) and fluorescence monitoring.
Analytical Sensitivity and Specificity: Greater than 99 percent.
Limitations: Only the targeted CYP2C19 variants will be detected by this panel, and assumptions about phase and content are made to assign alleles. Publically available sources such as the www.pharmvar.org or www.pharmgkb.org provide guidance on phenotype predictions and allele frequencies. Diagnostic errors can occur due to rare sequence variations. Risk of therapeutic failure or adverse reactions with CYP2C19 substrates may be affected by genetic and non-genetic factors that are not detected by this test. This result does not replace the need for therapeutic drug or clinical monitoring.
Please note the information contained in this report does not contain medication recommendations, and should not be interpreted as recommending any specific medications. Any dosage adjustments or other changes to medications should be evaluated in consultation with a medical provider.
Laboratory Developed Test (LDT)
Whole blood is the preferred specimen. Saliva samples that yield inadequate DNA quality and/or quantity will be reported as inconclusive if test performance does not meet laboratory-determined criteria for reporting.
|Component Test Code*||Component Chart Name||LOINC|
- clopidogrel (Plavix)
- Cytochrome P450 2C19 Genotype
- protein pump inhibitors (PPIs)