Blood Phosphatidylethanol (PEth) Concentrations following Intensive Use of an Alcohol-based Hand Sanitizer

"But I didn't drink!": What to do with discordant phosphatidylethanol results

Liver transplantation (LT) teams must be adept at detecting, evaluating, and treating patients' alcohol use, given its prominence among psychological and behavioral phenomena which cause and contribute to liver diseases. Phosphatidylethanol (PEth) is a highly useful alcohol biomarker increasingly recommended for routine use in hepatology and LT. PEth is unique among alcohol biomarkers because of its wide detection window, high sensitivity and specificity, and the correlation of its numerical value with different patterns of alcohol use. Alongside myriad clinical opportunities in hepatology and LT, PEth also confers numerous challenges: little guidance exists about its clinical use; fearing loss of LT access and the reactions of their clinicians and families, candidates and recipients are incentivized to conceal their alcohol use; and liver clinicians report lack of expertise diagnosing and treating substance-related challenges. Discordance between patient self-reported alcohol use and toxicology is yet another common and particularly difficult circumstance. This article discusses the general toxicological properties of PEth; explores possible scenarios of concordance and discordance among PEth results, patient history, and self-reported drinking; and provides detailed clinical communication strategies to explore discordance with liver patients, a key aspect of its use.

The alcohol biomarker phosphatidylethanol (PEth) - test performance and experiences from routine analysis and external quality assessment

Phosphatidylethanol (PEth) are membrane molecules formed from phosphatidylcholine and ethanol through transphosphatidylation catalyzed by phospholipase D. Measurement of the main PEth form 16:0/18:1 is used as a specific and sensitive alcohol biomarker, since its formation requires ethanol, it accumulates in the blood upon repeated ethanol exposure, and it is only slowly eliminated during abstinence. PEth formation correlates with alcohol intake at the population level, albeit with considerable inter-individual variation as for the half-life during withdrawal. Over the past decade, the use of PEth has increased significantly and the applications have broadened. In Sweden, routine decision limits and the interpretation of test results for PEth were harmonized in 2013, using < 0.05 µmol/L (∼35 µg/L) as the recommended lower reporting limit and values > 0.30 µmol/L (∼210 µg/L) to indicate regular high alcohol intake. Routine test results show a large variation with about half being < 0.05 µmol/L and some even exceeding 10 µmol/L. In 2013, an external quality assessment (EQA) scheme for PEth 16:0/18:1 measurement in whole blood was also started (Equalis, Uppsala, Sweden), presently involving 56 laboratories from 13 countries. The agreement of PEth results between the laboratories has gradually improved to a CV < 15%. The current clinical and scientific information suggests that PEth values below the lower reporting limit (typically ∼0.03-0.05 µmol/L, or ∼20-35 µg/L) indicates sobriety or only low or occasional alcohol consumption, while regular high alcohol intake at levels corresponding to harmful drinking is required in most cases to reach PEth values > 0.30 µmol/L.

Development and Validation of Seven Phosphatidylethanol Homologues in Dried Blood Spots Including Preliminary Results after Excessive Use of an Ethanol-Based Hand Sanitizer

Phosphatidylethanol (PEth) has become a widespread marker offering an up to 4-week retrospective window to detect alcohol use. Due to the pandemic of coronavirus disease 2019, ethanol-based hand sanitizers are frequently used. The aim of this study was to develop and validate a method for the determination of up to seven different homologues of PEth from dried blood spots (DBSs) after use of an ethanol-based hand sanitizer. The objectives of its preliminary application were to prove whether a threshold of 20 ng/mL for PEth 16:0/18:1 is reached and whether other homologues are formed as well as if positive findings of urinary ethyl glucuronide (UEtG) can be observed with respect to assess monitoring of abstinence control programs. Ten volunteers (8 occasional and 2 regular drinkers) were recruited to excessively use an ethanol-based hand sanitizer on 5 successive days. DBSs and urine samples were collected daily. PEth and UEtG were determined by liquid chromatography--tandem mass spectrometry. In total, two volunteers with initial PEth 16:0/18:1 concentrations of 19.3 and 14.6 ng/mL exceeded the threshold of 20 ng/mL six times. Subjects drinking daily or almost daily had starting PEth 16:0/18:1 concentrations of 242 and 354 ng/mL, showing a decline of PEth concentrations in six out of the seven homologues over 5 days. In teetotalers, formation of PEth species could not be observed. Thus, not satisfying requirements in an alcohol monitoring program with initial PEth-negative blood cannot be explained by a frequent use of ethanol-based hand sanitizer only. In cases of regular alcohol consumption, PEth homologues are not likely to be further influenced. However, results indicated that individuals with a PEth concentration close to 20 ng/mL are at risk of exceeding the threshold by using ethanol-based hand sanitizer.

PEth 16:0/18:1 and 16:0/18:2 after consumption of low doses of alcohol-A contribution to cutoff discussion

Phosphatidylethanol in blood has gained recognition as a direct alcohol biomarker. Although different cutoffs have been suggested, there is no consensus for differentiating abstinence from alcohol consumption. In this study, 75 participants (72% female) consumed 20 g of ethanol on three consecutive evenings. Blood was sampled on each following day and PEth 16:0/18:1 and 16:0/18:2 were determined. PEth 16:0/18:1 ranged from 8.9-21.5, 8.7-19.3, and 8.8-42.3 ng/ml and PEth 16:0/18:2 from 8.7-31.7, 9.0-39.3, and 9.4-43.0 ng/ml after the respective days of ethanol consumption. PEth 16:0/18:1 yielded a sensitivity of 25%, 45%, and 49% and PEth 16:0/18:2 of 40%, 61%, and 68% for the consumption days, respectively (cutoff 10 ng/ml). PEth 16:0/18:1 reached >20 ng/ml in five samples overall. Sensitivity of PEth 16:0/18:2 > 20 ng/ml was better with 35% after the three drinking days. Overall, PEth 16:0/18:1 was >35 ng/ml in one sample and PEth 16:0/18:2 in three samples. Significantly, more women had PEth 16:0/18:1 > 10 ng/ml after the third day of consuming 20 g of alcohol (p = 0.02) and PEth 16:0/18:2 > 10 ng/ml after the second (p = 0.023) and the third (p = 0.002) consumption, which can be led back to the higher blood alcohol concentration women reach after consuming the same alcohol amount as men. Although the response rates of PEth to alcohol uptake are subject to strong interindividual differences, results suggest that PEth cutoff should be lowered for better detection of consumption of low to medium amounts of alcohol. Furthermore, it is advantageous to analyze both PEth 16:0/18:2 and 16:0/18:1.