Morjana N, Yau H, Rea D, Ruttle D, Jones H, Siefring G, Christenson R. The Emit® 2000 Cyclosporine Specific Assay, Extended Range: development of an application protocol for the V-Twin® analyzer.
Biotechnol Appl Biochem 2011;
58:476-82. [PMID:
22172110 DOI:
10.1002/bab.43]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 07/13/2011] [Indexed: 11/12/2022]
Abstract
We evaluated a new protocol for measurement of cyclosporine A (CsA) 2 H after dose (C2) 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®/TDxFLx® assay. 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 C2 protocol on the V-Twin® analyzer provides acceptable assay performance and accurate determination of whole blood CsA drawn at 2 H after dose.
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