Background: We performed a 3-way comparison on the Osmetech eSensor(R), AutoGenomics INFINITI(TM), and a real-time PCR method (ParagonDx(TM) reagents/Stratagene(R) RT-PCR platform) for their FDA-cleared warfarin panels, and additional polymorphisms (CYP2C9 *5, *6, and *11 and extended VKORC1 panels) where available. Methods: One hundred de-identified DNA samples were used in this IRB-approved study. Accuracy was determined by comparison of genotyping results across three platforms. Any discrepancy was resolved by bidirectional sequencing. The CYP4F2 on Osmetech was validated by bi-directional sequencing. Results: Accuracies for CYP2C9 *2 and *3 were 100% for all 3 platforms. VKORC1 3673 genotyping accuracies were 100% on eSensor and 97% on Infiniti. CYP2C9 *5, *6 and *11 showed 100% concordance between eSensor and Infiniti. VKORC1 6484 and 9041 variants compared between ParagonDx and Infiniti analyzer were 100% (6484) and 99% (9041) concordant. CYP4F2 was 100% concordant with sequencing results. The time required to generate the results from automated DNA extraction-to-result was approximately 8 h on Infiniti, and 4 h on eSensor and ParagonDx, respectively. Conclusions: Overall, we observed excellent CYP2C9 *2 and *3 genotyping accuracy for all three platforms. For VKORC1 3673 genotyping, eSensor demonstrated a slightly higher accuracy than the Infiniti, and CYP4F2 on Osmetech was 100% accurate. (C) 2009 Elsevier B.V. All rights reserved.