Impact of a single packed red blood cell unit on recipient phosphatidylethanol

Phosphatidylethanol (PEth) is a marker of alcohol consumption present on erythrocytes. Consensus guidelines suggest that PEth concentrations ≥20 ng/mL and ≥ 200 ng/mL are consistent with alcohol consumption or chronic excessive consumption, respectively. However, packed red blood cell (pRBC) transfusion is a potential source of PEth in transfusion recipients. Currently, the prevalence of this phenomenon and the magnitude of PEth elevation after transfusion of a single pRBC unit remain uncertain. This study evaluated the impact of single-unit pRBC transfusion on observed PEth concentrations in recipients. The 16:0/18:1 homologue of PEth was measured in pre-transfusion, post-transfusion, and pRBC samples using liquid chromatography - tandem mass spectrometry with lower limit of quantitation (LLOQ) 10 ng/mL. In 99 consecutively-enrolled recipients, pRBC transfusion was responsible for 60.9 % of post-transfusion PEth concentrations ≥LLOQ and 60.0 % of post-transfusion concentrations ≥20 ng/mL. In the full study population (n = 143), 56 recipients had pre-transfusion PEth