Quantification of Seven Ethanol Biomarkers in Blood, Oral Fluid, and Urine in Samples from a Controlled Drinking and Vaping Crossover Study

Ethanol been identified in electronic cigarette (e-cig) liquids (e-liquids). Anecdotal reports claim use of an e-cig caused a positive drug test for ethanol, or one of it’s metabolites. Ethyl glucuronide (EtG) and ethyl sulfate (EtS), are the most common biomarkers to assess ethanol consumption. Other biomarkers include 5-hydroxyindolacetic acid (HIAA), 5-hydroxytryptophol (HTOL), and 5-hydroxytryptophol-β-D-glucuronide (GTOL), which stem from serotonin metabolism in the presence of ethanol. Phosphatidylethanol (PEth) is an abnormal phospholipid, with multiple possible isoforms, formed in the presence of ethanol. While most of these ethanol biomarkers are reportedly cleared from the body in days, the window of detection for PEth has been reported as days to months depending on the manner of drinking (i.e., moderate, chronic). The understanding of the formation and detection of these these seven analytes in blood, urine, and oral fluid varies, depending on analyte and matrix. While blood is the specimen gold standard for toxicology testing, oral fluid (OF) is gaining interest as a replacement. The aim of this study was to develop a unified method to quantitate the aforementioned biomarkers, including two of the most prevelant PEth isoforms, and investigate the relationship between biomarkers in blood and oral fluid using samples collected during a clinical study in which participants drank (placebo or active) and vaped (placebo or active) ethanol. Vaping a 20% ethanol e-liquid alone did not produce detectable concentrations of any biomarker. EtG and EtS were the only two biomarkers present in all blood samples following oral alcohol consumption. One participant had both PEth isoforms present in blood, including the pre-session baseline collection, indicating previous ethanol consumption. A unified analytical method can help streamline laboratory operations, while expanding the interpretive value of the analytical results.