Summary & Overview
CPT 81478: Genetic Testing for CYP2C19 Drug Metabolism
CPT code 81478 represents genetic analysis of the CYP2C19 gene, a key enzyme involved in drug metabolism. This test identifies common genetic variants that can influence how patients process medications, impacting treatment decisions across a range of clinical scenarios including cardiovascular disease and mental health. The code is widely recognized in medical genetics and pathology, and is typically performed in laboratory settings.
Blue Cross Blue Shield is a primary payer covered in this analysis. Readers will gain insight into payer coverage, relevant clinical indications, and associated billing practices for genetic testing services. The publication also highlights related CPT codes for other cytochrome P450 gene analyses, common modifiers used in laboratory billing, and the clinical context for ordering CYP2C19 testing. Benchmarks and policy updates are provided to inform stakeholders about current trends in genetic testing reimbursement and utilization.
This summary offers a comprehensive overview of CPT code 81478, including its clinical significance, payer landscape, and billing considerations. Healthcare professionals, laboratory administrators, and policy analysts will find actionable information to support decision-making in genetic testing services.
CPT Code Overview
CPT code 81478 is used for genetic testing of the CYP2C19 gene, which plays a critical role in drug metabolism. This test analyzes common variants such as *2, *3, *4, *8, and *17 to help determine how a patient may respond to certain medications. The service type is genetic testing, and it is typically performed in a laboratory setting (POS 81). This testing provides valuable information for clinicians to tailor drug therapy based on individual genetic profiles.
Clinical & Coding Specifications
Clinical Context
A patient is referred for genetic testing to evaluate their CYP2C19 gene variants, which influence drug metabolism. This is commonly performed in a laboratory (POS 81) setting. The test is ordered when a patient is being considered for medications metabolized by CYP2C19, such as certain antiplatelet drugs or antidepressants. The workflow involves the provider collecting a specimen, sending it to a laboratory specializing in molecular genetics, and receiving a report detailing the patient's CYP2C19 genotype. This information assists in tailoring drug therapy based on the patient's genetic profile.
Coding Specifications
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Modifiers:
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Modifier
26: Indicates the professional component of the laboratory service, typically used when the interpretation of the genetic test is performed by a qualified provider. -
Modifier
91: Used when the laboratory test is repeated for the same patient, such as monitoring changes or confirming previous results.
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Provider Taxonomies:
| Taxonomy Code | Specialty Name |
|---|---|
207SG0201X | Medical Genetics, Ph.D. Medical Genetics |
207ZP0213X | Pathology, Molecular Genetic Pathology |
207Q00000X | Family Medicine Physician |
These taxonomies represent providers who may order, interpret, or be involved in the clinical management of genetic testing for CYP2C19.
Related Diagnoses
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Z13.79: Encounter for other screening for genetic and chromosomal anomalies- Used when the test is performed as a screening measure to identify genetic variants affecting drug metabolism.
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Z15.89: Genetic susceptibility to other disease- Indicates the patient has a genetic predisposition to certain diseases, relevant for pharmacogenetic testing.
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Z79.899: Other long term (current) drug therapy- Applied when the patient is on chronic medication, and genetic testing is needed to optimize therapy.
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I25.10: Atherosclerotic heart disease of native coronary artery without angina pectoris- Relevant for patients prescribed antiplatelet drugs metabolized by CYP2C19, such as clopidogrel.
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F32.9: Major depressive disorder, single episode, unspecified- Used when genetic testing is performed to guide antidepressant therapy, as CYP2C19 affects metabolism of certain psychiatric medications.
Related CPT Codes
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81225: CYP2C9 (cytochrome P450, family 2, subfamily C, polypeptide 9) gene analysis, common variants. Used for evaluating drug metabolism similar to CYP2C19, often ordered together for comprehensive pharmacogenetic profiling. -
81226: CYP2D6 (cytochrome P450, family 2, subfamily D, polypeptide 6) gene analysis, common variants. Related to drug metabolism; may be ordered alongside81478for broader assessment. -
81227: CYP3A4 (cytochrome P450, family 3, subfamily A, polypeptide 4) gene analysis, common variants. Another cytochrome P450 gene relevant to drug metabolism, sometimes included in panels. -
81479: Unlisted molecular pathology procedure. Used when a molecular pathology test does not have a specific CPT code; may be an alternative if testing for rare CYP2C19 variants not covered by81478.
National Reimbursement Benchmarks
For CPT code 81478, national mean rates for Blue Cross Blue Shield and BUCA (average commercial) are both $80.02. Medicare rates are not available in the input, so a comparison between commercial and Medicare rates cannot be made.
Rate dispersion for both Blue Cross Blue Shield and BUCA is minimal, with the 25th, 50th, and 75th percentiles all at $80.00. This indicates a very tight range, with no variation between the lower and upper quartiles for these payers.
The table and chart below present the full breakdown of national benchmarks for CPT code 81478 by payer.
Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.