Development and validation of an LC-MS/MS method to quantify the alcohol biomarker phosphatidylethanol 16:0/18:1 in dried blood spots for clinical research purposes.

Phosphatidylethanol (PEth) is a group of phospholipids detectable in red blood cells exclusively following ethanol consumption. The primary PEth analog, PEth 16:0/18:1, has an extended half-life in red cells, providing a long window of detection and tremendous potential for the quantification of cumulative alcohol consumption. We developed and validated an LC/MS-MS method to quantify PEth 16:0/18:1 in dried blood spots (DBS) for clinical research purposes. Method development and validation followed FDA guidance but expanded on prior published methods through the evaluation of additional DBS-specific factors such as sample hematocrit, punch location, and spot volume. This method was applied to the quantification of PEth in participant samples.