Characterization of the alcohol biomarker phosphatidylethanol in donor whole blood and apheresis red blood cells: Implications for transfusion recipients

Introduction Phosphatidylethanol (PEth) is a long‐term marker of alcohol consumption used frequently in clinical scenarios such as liver transplant evaluation. Recent cases have demonstrated that packed red blood cell (pRBC) transfusion creates the potential for artificial elevation or decrease of observed PEth concentrations in recipients. Very little is known about the prevalence or stability of PEth in pRBCs. Methods Apheresis and whole‐blood (WB) donations were tested for PEth using liquid chromatography – tandem mass spectrometry with limit of quantitation 10 ng/mL. Units were stored under routine blood bank conditions to evaluate the stability of PEth and the impact of irradiation. Results Over 40% of apheresis and WB donors had PEth ≥10 ng/mL (maximum observed 587 ng/mL). As WB units were processed into component pRBCs, PEth concentrations increased and were higher than donor WB levels (EDTA sample) prior to collection (maximum observed 711 ng/mL). Storage for up to 5 weeks post donation resulted in mean 17.3% decrease in PEth‐positive units; in contrast to a prior report, we observed no PEth formation in units with negative (