Preanalytical variables affecting the quantification of fatty acid ethyl esters in plasma and serum samples

Background: Fatty acid ethyl esters (FAEEs) are cytotoxic nonoxidative etha nol metabolites produced by esterification of fatty acids and ethanol. FAEE s are detectable in blood up to 24 h after ethanol consumption. The objecti ve of this study was to assess the impact of gender, serum or plasma trigly ceride concentration, time and temperature of specimen storage, type of alc oholic beverage ingested, and the rate of ethanol consumption on FAEE conce ntrations in plasma or serum. Methods: For some studies, subject were recruited volunteers; in others, re sidual blood samples after ethanol quantification were used. FAEEs were iso lated by solid-phase extraction and quantified by gas chromatography-mass s pectrometry. Results: For weight-adjusted amounts of ethanol intake, FAEE concentrations were twofold greater for men than women (P less than or equal to 0.05). Ac counting for triglycerides improved the correlation between blood ethanol c oncentrations acid FAEE concentrations for both men (from r = 0.640 to r = 0.874) and women (from r = 0.619 to r = 0.673). FAEE concentrations did not change when samples were stored at or below 4 degrees C, but doubled when stored at room temperature for greater than or equal to 24 h. The type of a lcoholic beverage and rate of consumption did not affect FAEE concentration s. Conclusion: These studies advance plasma and serum FAEE measurements closer to implementation as a clinical test for ethanol intake. (C) 1999 American Association for Clinical Chemistry.