Pharmacogenetic Test
Definition
Examines how your genes affect the way your body responds to certain medicines. In a blood, saliva or cheek swab sample, it detects gene variants that affect the absorption, breakdown and effectiveness of drugs.
Purpose, for which drugs and conditions:
| Area | Gene | Drug/Condition |
|---|---|---|
| High cholesterol | SLCO1B1 | Statin tolerance |
| Depression | CYP2D6 / CYP2C19 | Antidepressant metabolism |
| Clot prevention | , | Warfarin dose adjustment |
| HIV | HLA-B, CYP2B6 | Side effect prediction |
| Multiple sclerosis | TPMT / NUDT15 | Azathioprine response |
| Cancer treatment | HER2 | Trastuzumab |
| TPMT | Mercaptopurine | |
| UGT1A1 | Irinotecan |
Results
The result report describes the changes in the gene and helps the physician recommend the appropriate treatment or dose.
Terms you will see in the report, CPIC standard terminology
The terms used in pharmacogenetic reports have been standardized by the Clinical Pharmacogenetics Implementation Consortium (CPIC). In a study conducted with 58 experts using the Delphi method, 90% of the experts reached consensus on the final set of terms.
Enzyme activity phenotypes (for drug-metabolizing enzymes such as CYP2D6, CYP2C19, TPMT, DPYD), expert consensus 91.7%:
| Term | Meaning |
|---|---|
| Ultrarapid metabolizer (Ultrarapid) | The enzyme works much faster than expected |
| Normal metabolizer (Normal) | Expected enzyme activity. Formerly called "extensive metabolizer", this term has been abandoned |
| Intermediate metabolizer (Intermediate) | Reduced activity |
| Poor metabolizer (Poor) | Markedly reduced or almost no activity |
Allele function terms:
| Term | Meaning |
|---|---|
| Increased function (Increased function) | Increased enzyme activity |
| Normal function (Normal function) | Normal enzyme activity |
| Decreased function (Decreased function) | Decreased enzyme activity |
| No function (No function) | No enzyme activity |
| Uncertain function (Uncertain function) | No literature defining the function |
| Conflicting function (Conflicting function) | Data on the function are conflicting |
Why it was standardized: Different terms were being used for different laboratories and genes. The CPIC standard makes reports comparable across laboratories and allows them to be shared consistently in electronic health records.
Note for the glossary: The terminology used in Genetiks' pharmacogenetic reports should be confirmed. If the CPIC standard is used, the table above applies directly; if not, the laboratory's own terms should be mapped to it.
Risks and Limitations
A frequently misunderstood point:
The test cannot diagnose any disease and cannot provide information about your risk of developing a disease. The results show how medicines may affect you; they do not provide information about your health status.
In other words, a pharmacogenetic test is not a "genetic disease screening"; it only provides information about drug response.