Ordering Recommendation

Assesses genetic risk of abnormal drug metabolism for CYP2C19 substrates. May aid in drug selection and dose planning for drugs metabolized by CYP2C19.

Mnemonic
2C19GENO
Methodology

Polymerase Chain Reaction/Fluorescence Monitoring

Performed

Varies

Reported

5-10 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

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.

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL) OR Transport the Saliva Collection Device.

Storage/Transport Temperature

Whole Blood: Refrigerated.
Saliva:
Room temperature.

Unacceptable Conditions

Plasma or serum. Specimens collected in sodium heparin or lithium heparin.

Remarks
Stability

Whole Blood: Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month
Saliva:
Ambient: 2 weeks; Refrigerated: Unacceptable; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

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.

Compliance Category

Laboratory Developed Test (LDT)

Note

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.

Hotline History
N/A
CPT Codes

81225

Components
Component Test Code* Component Chart Name LOINC
3001509 2C19GENO Specimen 31208-2
3001510 CYP2C19 Genotype 57132-3
3001511 2C19GENO Interpretation 50398-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • 2C19
  • antidepressants
  • clopidogrel (Plavix)
  • CYP2C19
  • Cytochrome P450 2C19 Genotype
  • omeprazole
  • protein pump inhibitors (PPIs)
  • voriconazole
CYP2C19