The emit ?R 2000 cyclosporine specific assay, extended range: Development of an application protocol for the V-Twin ?R Analyzer

摘要

We evaluated a new protocol for measurement of cyclosporine A (CsA) 2 H after dose (C_2) on the V-Twin analyzer. Imprecision, recovery, and linearity were determined using CsA-spiked blood pools. Accuracy was evaluated using specimens from renal, cardiac, and liver transplant patients, and results were compared with those from liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the Abbott TDx /TDxFLxassay. Cross-reactivity and interferences were assessed in the presence of 800 ng/mL CsA. Imprecision coefficients of variation were 3.3%-4.8% (within run) and 5.9%-8.7% (total). Recovery was within 10% of the expected values. Linearity was 350-2,000 ng/mL. Calibration was stable for ≥ 2 weeks. Method comparison showed regression statistics: V-Twin= 1.01 × LC tandem MS + 36.1, r = 0.971; V-Twin= 1.13 × Abbott - 92.4, r = 0.969. Metabolite cross-reactivity and interference (endogenous substances and drugs) were within ±10%. The C_2 protocol on the V-Twinanalyzer provides acceptable assay performance and accurate determination of whole blood CsA drawn at 2 H after dose.