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Measurement of mycophenolic acid in plasma or serum by a commercial enzyme inhibition technique in comparison with a high performance liquid chromatography method
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Dustin R. Bunch
Published/Copyright:
July 8, 2008
Abstract
Background: Mycophenolic acid (MPA) is the primary active metabolite of the immunosuppressant mycophenolate mofetil. High performance liquid chromatography (HPLC) is commonly used for therapeutic drug monitoring (TDM) of MPA but requires batched runs. Recently, an enzyme inhibition assay (EIA) was approved for MPA TDM on random-access platforms using either serum or EDTA plasma. We evaluated the EIA on a Roche Integra 400 using serum and heparinized plasma in comparison with a validated HPLC method.
Methods: Heparinized plasma from leftover clinical samples on which MPA was ordered along with paired serum samples, drawn at the same time for other clinical tests, were used for the method comparison.
Results: The EIA was linear from 3.1 to 44.0 μmol/L with an accuracy of 93.9%–107.1%. The intra- and inter-day variations were 0.5%–2.7% and 1.6%–2.1%, respectively. The limit of detection was 0.8 μmol/L and the limit of quantification was 3.1 μmol/L. The method showed a mean bias of 0.6 μmol/L (7.6%) in serum samples (3.1–34.1 μmol/L) vs. the HPLC method using paired plasma (n=229). Heparinized plasma (n=114) vs. serum showed a mean bias of –0.1 μmol/L (–1.6%) by the EIA.
Conclusions: The random-access EIA on Integra 400 is acceptable for clinical MPA TDM in either serum or heparinized plasma.
Clin Chem Lab Med 2008;46:1281–4.
Keywords: COBAS Integra; enzyme inhibition assay; high performance liquid chromatography (HPLC); mycophenolic acid; therapeutic drug monitoring
Received: 2008-2-26
Accepted: 2008-4-24
Published Online: 2008-07-8
Published in Print: 2008-09-01
©2008 by Walter de Gruyter Berlin New York
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Keywords for this article
COBAS Integra;
enzyme inhibition assay;
high performance liquid chromatography (HPLC);
mycophenolic acid;
therapeutic drug monitoring
Articles in the same Issue
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- Opinion Papers
- Local regression: a new approach for measurement system comparison analysis
- Accuracy in clinical chemistry – who will kiss Sleeping Beauty awake?
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