- 作者：Sibylle Bremer-Streck ; Michael Kiehntopf ; Stefan Ihle ; Klas Boeer
- 关键词：Digitoxin ; LC-MS/MS ; Interference
- 刊名：Clinical Biochemistry
- 出版年：November, 2013
- 年：2013
- 卷：46
- 期：16-17
- 页码：1728-1733
- 全文大小：387 K
Objectives
Therapeutic drug monitoring of digitoxin is strongly recommended but metabolites of digitoxin and digitoxin-like immunoreactive substances may interfere with widely used immunoassays. Recently evaluated assays on LC-MS/MS have the drawback of long turnaround time. We sought to evaluate a specific method on LC-MS/MS optimizing sample preparation thereby significantly reducing turnaround time.Design and methods
Linearity, functional sensitivity, and precision of the method were established. External quality control samples were used for the evaluation of accuracy of the LS-MS/MS method. In addition, digitoxin concentrations in 221 samples were measured by LC-MS/MS and immunoassay.
Results
Linearity was validated between 0.15 and 80 ng/mL. Limit of quantification was established at 0.14 ng/mL. Between-day imprecision lay between 1.4 and 4.9% and meets the conditions required for routine analysis. Comparison to results obtained by immunoassay revealed a mean difference of 鈭?#xA0;1.2 ng/mL.
Conclusions
By optimizing preparation steps turnaround time was shorter for LC-MS/MS than for immunoassay. This did not result in increased susceptibility to matrix effects. Analytical performance was sufficient for routine analysis. Therefore, the method is suitable for routine therapeutic drug monitoring of digitoxin.