Concordance Between Commercial Pharmacogenetic Test Recommendations and CPIC Guidelines for Antidepressant Therapy

Pharmacogenetic testing is increasingly used to guide clinicians in selecting medications tailored to a patient’s genetic profile. Although various government-supported organizations aim to establish standardized guidelines for testing and interpretation, adherence to these best practices is often inconsistent. Many pharmacogenetic testing companies rely on proprietary methods for analyzing and reporting results, which can result in inconsistencies across companies and potential differences in how results are interpreted. This study aimed to assess how commercial pharmacogenetic testing vendors differ in translating genotypes to phenotypes and in generating medication recommendations compared with Clinical Pharmacogenetic Implementation Consortium (CPIC) guidelines. We performed a retrospective chart review in a large rural healthcare system that utilizes two approved pharmacogenetic testing companies. A total of 100 patients were included, evenly split between the two vendors. Analysis focused on CYP2B6, CYP2C19, and CYP2D6 genes. Medication recommendations for key drug-gene pairs—sertraline (CYP2B6/CYP2C19), escitalopram (CYP2C19), and paroxetine (CYP2D6)—were compared to CPIC guidance, incorporating updates from the 2023 SSRI guideline. To standardize comparison, we developed a three-tier binning system reflecting CPIC-based actions: green for no changes needed, yellow for monitoring suggested, and red for interventions or alternative therapy recommended. This approach allowed systematic evaluation of concordance between commercial reports and guideline-based recommendations. Among the 250 genotype-to-phenotype translations analyzed, 32 (12.8%) differed from CPIC guideline interpretations, all originating from Company A. When examining 266 binned medication recommendations, 114 (42.9%) showed discrepancies between the commercial reports and CPIC guidelines. Breaking this down by vendor, Company A accounted for 93 of the discrepancies, while Company B accounted for 21, as determined using the novel binning system. Notable differences were identified between the interpretations and recommendations of the two pharmacogenetic testing companies, raising concern that such discrepancies could prompt providers to make medication decisions that deviate from CPIC clinical practice guidelines. This misalignment may contribute to suboptimal patient outcomes, decreased satisfaction for both patients and providers, and diminished trust in pharmacogenetic testing. To address these inconsistencies, greater adherence to CPIC guidelines and increased transparency in interpretation methods are recommended.