High-Throughput LC-MS/MS Method for Determination of the Alcohol Use Biomarker Phosphatidylethanol in Clinical Samples by Use of a Simple Automated Extraction Procedure—Preanalytical and Analytical Conditions

Background: Phosphatidylethanol (PEth) is an alcohol use biomarker with higher clinical sensitivity and specificity than commonly used alcohol markers. Since its introduction as a clinical alcohol-marker in 2006, the number of samples sent to our laboratory for the determination of PEth has shown a strong annual increase. This has prompted the need to develop a cost-effective and reliable analytical procedure with high capacity. Methods: An LC-MS/MS method for the determination of PEth 16:0/18:1 with a short turnaround time (3 min) has been evaluated with respect to accuracy, sensitivity, and precision. We compared this method with a previously used HPLC method, as well as a manual and a simplified automated method for sample workup, and investigated potential causes of analytic and preanalytic errors. Results: The method shows limits of detection and quantification of 0.0075 μmol/L (5.2 ng/mL) and Conclusions: This LC-MS/MS method with automated sample workup is well suited for a clinical laboratory with LC-MS/MS experience and has the capability, proven from several years of use, to produce reliable PEth results in a high-volume laboratory (>50000 clinical samples/year).