How to Read Pharmacogenetic Results and Compare Reports

Already have a pharmacogenetic (PGx) report? Start by separating the laboratory’s reported genetic result from the conclusions drawn from it. You can reuse some results without another DNA sample, but compatibility and useful medication coverage depend on the information actually present. A new report cannot recover an untested or unreported gene.

A gene name such as CYP2C19 identifies the result being discussed. A medication name or colored category is not a gene result. Keep each gene attached to its own result when copying information; do not infer missing values from another gene or from the provider’s name.

Many PGx reports use star-allele notation. For example, CYP2C19 *1/*2 describes two alleles for one gene. A star number is an allele identifier, not a score or a count of risk. Other genes may use different naming systems. Copy the complete result exactly; notation that looks similar can have a different meaning.

Terms such as normal or intermediate metabolizer summarize the expected function assigned to a result. They are not unique identifiers for the underlying alleles. Multiple allele pairs can share a phenotype, so a phenotype label cannot reliably be converted back into a diplotype.^[1]

Medication advice depends on the drug, the applicable evidence, and sometimes multiple genes. Do not transfer a recommendation from one drug to another simply because they share a gene. Pharmacogenetic information does not include everything needed for prescribing.^[3]

A changed classification can have several causes. First check whether the two reports contain the same underlying gene and complete allele pair.

Different tested variants or methods. A laboratory may test a different set of variants, and CYP2D6 copy-number or structural-variant detection can differ. A matching gene name does not establish equivalent testing.^[2]

Different translation rules. Allele function assignments and the boundaries between phenotype categories can change. The CPIC/DPWG CYP2D6 consensus work documents why standardized translation matters.^[1]

Different medication rules. Reports can combine genes differently, use different evidence versions, or assess different medications. Even with matching input values, a second service need not reproduce the original laboratory’s colors or wording. Gene2Rx applies published CPIC, FDA, and DPWG guidance, and each report records the guideline version it used.

Clinical factors outside the genetic result. Other medicines and patient factors can affect response. Bring those details to the clinician comparing the reports. A genetic report is not a complete medication review.^[3]

Commercial panels such as GeneSight and Genomind report on the medications they were ordered for. The same genotypes often have published guidance for many other medications, from statins and blood thinners to pain medications and acid reducers. A second interpretation can show you those, and lay out how each recommendation was reached.

Gene2Rx can build a Panel Report from results you already have. You enter each gene's two star alleles, see which medications they cover before you pay, and get a web and PDF report for $19. Gene2Rx does not run another test or see your original lab report, so it interprets exactly what you enter. A gene you don't enter is not assessed, and that is not the same as a normal result. For example, a CYP2C9 result alone is not a complete warfarin assessment, because warfarin guidance also uses VKORC1 and clinical factors.^[4] Antidepressant guidance can likewise depend on more than one gene.^[5]

• 23andMe Drug Response: What You'll Actually See in a Report From Your Data
• 23andMe Pharmacogenetics: How to Get a Drug Response Report From Your Existing Data
• AncestryDNA for Drug Testing: Get Pharmacogenetics From Your Ancestry Data
• Dante Labs Pharmacogenetics: Turn Your Dante WGS Data Into a PGx Report
• Genera Pharmacogenetics: Turn Your Genera Raw Data Into a Drug Response Report
• Looking for a GeneSight Alternative? Here's the Short Answer

No. The genotype describes the reported alleles; the phenotype is a function category assigned to them. A phenotype alone does not identify a unique allele pair.

No. A normal genetic interpretation covers only the relevant assessed inputs. Other genes, interactions, medical conditions, and non-genetic factors can still affect medication safety and response.

Keep it as reported. Notation such as *2x2 (a gene duplication) or *36+*10 (a tandem arrangement) changes how much enzyme activity you have, so dropping it changes the result. Gene2Rx's entry form lets you choose the copy number and the common tandems for CYP2D6. If your report gives xN without a count, Gene2Rx assumes two copies, the most common number, and tells you when a third copy would change the result.

No. First compare the full allele calls, testing methods, and interpretation versions. Ask the laboratory or clinician to explain the discrepancy. A transcription correction is appropriate only when an entry was copied incorrectly.

Most GeneSight and Genomind reports list star-allele genotypes Gene2Rx can use, but it depends on each gene. Phenotype labels, medication colors, HLA results, and genes Gene2Rx doesn't cover (such as MTHFR) can't be entered. The GeneSight and Genomind pages show where to find your genotypes, and the entry form lists every allele Gene2Rx accepts.