The Emit® 2000 Sirolimus Assay* on the v-Twin®/Viva E® Analyzers

Abstract

Poster Abstracts402 MONDAY Supplement to Transplantation July 27, 2008, Volume 86 Number 2S complexes. The supernatant is then transferred to a photometric cuvette where the enzyme tag is detected using a chromogenic substrate. Results: Analytical and functional sensitivity are 9.5 and 25 ng/mL, respectively. The LoB and LoD are 15.0 and 22.5 ng/mL, respectively, based on a study per the CLSI EP-17A protocol. The method is linear to 500 ng/mL. Repeatability and within-lab reproducibility on patient pools were measured to be 5.9 and 7.3%CV at 82.5 ng/mL, 4.2 and 6.1%CV at 132.2 ng/mL, 3.5 and 4.3%CV at 219.4 ng/mL, and 3.6 and 3.9%CV at 369.2 ng/mL cyclosporine respectively per the CLSI EP5-A2 protocol over a 20 day testing interval. Split sample correlation between the revised method (rCSA) and the existing method (CSA) gave a linear regression fi t of: rCSA = 1.035×CSA -6.5, r=0.994, n =184, range = 19 -468 ng/mL. Cross-reactivity with metabolite AM9 was <2%. No signifi cant cross-reactivity was detected in samples spiked with 100 ng/mL tacrolimus, 5000 ng/mL rapamycin, 200 ug/mL MPA or 400 ug/mL MPAG. No signifi cant interference (<10%) was found for 60 mg/dL bilirubin, 1500 mg/dL triglyceride, 500 mg/dL cholesterol, 500 IU/mL rheumatoid factor, type I and II HAMA, 4 g/dL and 12 g/dL of total protein. Conclusion:The revised method showed signifi cant precision improvement at the analyte concentrations below 100 ng/mL, and provides accurate and fast measurements of cyclosporine on the Dimension system.