ABSTRACT
BACKGROUND: A variety of commercial genotyping assays is available to detect variants in the CYP2C9 and VKORC1 genes. The assay results are used in genotype-based warfarin dosing algorithms. We compared the performance of four such assay systems: Verigene, eSensor, Invader, and Luminex. METHODS: Result concordance and no call rates were determined on patient specimens tested on all four instruments. Turnaround times (TAT), hands-on time (HOT), pipetting steps and cost were obtained for runs of 1, 8 and 24 samples. RESULTS: The four assays were 100% concordant for the common CYP2C9 and VKORC1 alleles (n=100). Verigene had the shortest TAT and HOT for 1 and 8 samples. Verigene had the fewest pipetting steps for all sample sizes, while Invader had the most. Luminex had the longest TAT and highest cost for all sample run sizes. Verigene had the lowest cost for 1 and 8 samples and Invader the lowest for 24 samples. The no call rates for Verigene, Luminex, eSensor, and Invader were 10%, 4%, 1% and 0%, respectively. CONCLUSIONS: All assays gave comparable results for common variants. Each system offered unique advantages and disadvantages, whose relative importance depends on the needs of the adopting clinical laboratory.
Subject(s)
Aryl Hydrocarbon Hydroxylases/genetics , Genetic Techniques , Mixed Function Oxygenases/genetics , Warfarin/adverse effects , Algorithms , Cytochrome P-450 CYP2C9 , DNA/analysis , DNA/genetics , DNA/isolation & purification , Databases, Genetic , Dose-Response Relationship, Drug , Ethanol/chemistry , Genetic Techniques/economics , Genotype , Humans , Polymorphism, Single Nucleotide/drug effects , Time Factors , Vitamin K Epoxide ReductasesABSTRACT
The clinical significance of specimens with low sample-to-cutoff (S/Co) ratios in the Ortho VITROS chemiluminescence assay (CIA) for detection of antibodies to hepatitis C virus (HCV) was evaluated. In one study of 482 CIA-reactive samples, none of the 83 samples with S/Co ratios of < 5 was HCV RNA positive. In a subsequent study, 332 samples with S/Co ratios of between 1 and 20 were tested with the recombinant immunoblot assay (RIBA). None of the 163 samples with S/Co ratios of < 5 was RIBA positive, 83% were RIBA negative, and 28 samples (18%) were RIBA indeterminate. HCV RNA and/or clinical evidence of hepatitis was not found in the 27 indeterminate cases examined. These results show that over 99% of samples with very low S/Co ratios (< or = 5) have no evidence of HCV infection. Therefore, we suggest that the HCV antibody testing algorithm for the VITROS assay might be modified to eliminate supplemental testing of samples with very low S/Co ratios.
