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 (U-EtG) 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 U-EtG 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.