PEth-gate – Gränsvärdet på 0,3 mikromol/L felberäknat 2013?

Phosphatidylethanol (PEth) detected in blood for 3 to 12 days after single consumption of alcohol—a drinking study with 16 volunteers

In most studies, the alcohol marker phosphatidylethanol (PEth) was used to differentiate social drinking from alcohol abuse. This study investigates PEth's potential in abstinence monitoring by performing a drinking study to assess the detection window of PEth after ingesting a defined amount of alcohol. After 2 weeks of abstinence, 16 volunteers ingested a single dose of alcohol, leading to an estimated blood alcohol concentration (BAC) of 1 g/kg. In the week after drinking, blood and urine samples were taken daily; in the second week, samples were taken every other day. PEth 16:0/18:1 and 16:0/18:2 were analyzed in blood by online-SPE-LC-MS/MS. Ethyl glucuronide and ethyl sulfate were determined in urine for abstinence monitoring. Prior to start of drinking, PEth 16:0/18:1 exceeded 30 ng/mL in blood samples of five volunteers despite the requested abstinence period. Positive PEth values resulted from drinking events prior to this abstinence period. After the start of drinking, maximum BACs were reached after 2 h with a mean of 0.80 ± 0.13 g/kg (range: 0.61-1.11 g/kg). PEth 16:0/18:1 increased within 8 h to maximum concentrations (mean: 88.8 ± 47.0 ng/mL, range: 37.2-208 ng/mL). After this event, PEth was detectable for 3 to 12 days with a mean half-life time of approximately 3 days. PEth has a potential in abstinence monitoring, since PEth could be detected for up to 12 days after a single drinking event. Further investigations are necessary, to establish cut-off levels for PEth as diagnostic marker for the determination of drinking habits like abstinence, social drinking, or risky alcohol consumption.

Results:
The correlation between PEth and self-reported alcohol intake increased significantly over time, with the weakest correlation found at baseline (Spearman’s ρ=0.42) and the strongest at the 104-week follow-up (ρ=0.69). When used to indicate hazardous drinking according to Swedish guidelines (≥10 units per week), receiver operating characteristic analysis revealed PEth≥0.22 μmol/l to be the optimal cut-off.

Conclusions:
PEth is a useful outcome measure that can be used to validate subjective reports of current drinking. In a treatment setting aimed at controlled drinking, the accuracy of patients’ self-report measures seems to improve over time. In this context, a PEth value of≥0.22 μmol/l is a sensitive and specific indicator of hazardous drinking.

In Sweden, PEth levels above 0.30 μmol/l are routinely considered to be indicative of hazardous use, whereas levels between 0.05 and 0.30 μmol/l indicate moderate drink-ing.

How-ever, it is still debated whether the cut-off of 0.30 μmol/l is optimal for identifying hazardous drinking (Hahn et al.2016; Skråstad et al. 2023).

Hazardous drinking was defined as average weekly number of drinks larger than or equal to 10 for the last 2 weeks. All analyses were performed with R version 4.3.1 (R Core Team 2021).

In Sweden,current guidelines define hazardous drinking as a weekly alcohol intake of 10 or more standard drinks. When estimating a PEth value corresponding to this drinking level, ROC analysis revealed ≥0.22 μmol/l to be the optimal cut-off (Fig. 5).

PEth Median (range) 0.4 (0–2.9)
CDT Median (range) 1.7 (0.2–9.8)
Average number of standard drinks per week Median (range) 21.2 (0–77.4)