Cytochrome P450 2C19 (CYP2C19) 9 Variants (INACTIVE as of 01/04/16: Refer to November 2015 Hot Line for Replacement Test: 2012769, ACTIVE 01/04/16)
Ordering Recommendation
Polymerase Chain Reaction/DNA Hybridization/Electrochemical Detection
Tues, Fri
7-14 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
By report
Interpretive Data
Background Information for Cytochrome P450 2C19 (CYP2C19) 9 Variants:
Impaired drug metabolism causing adverse drug reactions or lack of drug response. Drugs metabolized by CYP2C19 include clopidogrel, S-mephenytoin, diazepam, R-warfarin, some antidepressants (eg, citalopram, amitriptyline, clomipramine), proton pump inhibitors (eg, omeprazole, lansoprazole), and antimalarials (eg, chloroguanide).
Autosomal recessive.
CYP2C19 allelic variants.
No variants detected is predictive of *1 functional alleles and normal enzymatic activity.
Variants Tested: (
Variants are numbered according to NM_000769 transcript).
Decreased function: *9 (c.431G>A); *10 (c.680C>T).
Non-functional: *2 (c.681G>A), *3 (c.636G>A), *4 (c.1A>G), *6 (c.395G>A), *7 (c.819+2T>A), *8 (c.358T>C).
Increased function: *17 (c.-806C>T; increased gene transcription).
Incidence of Poor Metabolizer Phenotype:
4 percent of Caucasians, 5 percent of African Americans, and up to 25 percent of Asians.
Drug dependent.
Clinical Sensitivity:
99 and 87 percent of clinically significant variants detected in Asians and Caucasians respectively; sensitivity is unknown in other ethnicities.
: Polymerase chain reaction, DNA hybridization, and electrochemical detection.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Only the targeted CYP2C19 variants will be detected. Variants in other genes will not be detected. Diagnostic errors can occur due to rare sequence variations. Variant detection is not a substitute for therapeutic drug monitoring or other clinical monitoring.
Overview of CYP (; nomenclature of CYP alleles (; drug substrates/inhibitors/inducers for CYP (

Compliance Statement C: The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing. Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

CPT Code(s)
Component Test Code*Component Chart NameLOINC
0051239CYP2C19 Variant57132-3
0051240CYP2C19 Variant57132-3
0051411CYP2C19 Predicted Phenotype62365-2
2001305CYP2C19 Specimen31208-2
* 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.
  • Amitriptyline
  • Clopidogrel
  • Cytochrome P450 2C19 Genotype by Sequencing Analysis, Saliva
  • Elavil
  • Escitalopram
  • Lexapro
  • Nolvadex
  • P450 2C19 Genotyping
  • Plavix
  • Tamoxifen
  • Treatment Resistant Antidepressant Panel