A simplified approach for determination of urinary ethyl glucuronide by gas chromatography–mass spectrometry

Does ethyl glucuronide in hair correlate with alcohol consumption? A comparative study with other traditional biomarkers among individuals with alcohol dependence syndrome

AIM

Ethyl glucuronide (EtG) in hair is a direct biomarker proven to be useful for the detection of chronic excessive alcohol use. This study investigated the association of self-reported alcohol consumption with traditional biomarkers: GGT, AST, ALT, CDT, and MCV in blood and a direct biomarker, hair EtG, in a total of 122 patients with alcohol dependence syndrome. The diagnostic accuracy of the biomarkers to differentiate heavy from non-heavy drinkers was also evaluated.

METHOD

GGT, AST, and ALT in serum were measured by Automated Chemistry Analyzer, MCV in blood was measured by Haematology Analyzer, serum CDT was analyzed by ELISA, and EtG in hair was evaluated by gas chromatography-mass spectrometry. The association between the biomarkers and the amount of alcohol consumed (self-reported) was determined using Spearman's rank correlation.

RESULTS

All participants showed EtG level above the cut-off (0.03 ng/mg). Hair EtG showed a statistically significant linear and positive correlation with the amounts (in grams) of alcohol consumed (r = 0.60; p < 0.001). No correlation was observed among the traditional biomarkers and the quantity of alcohol consumed. Also, EtG showed an excellent receiver operating characteristic (ROC) curve (98%) with good sensitivity (85%) and specificity (60%) to classify heavy drinkers among individuals with alcohol dependence syndrome.

CONCLUSION

Hair EtG can be helpful to estimate retrospective alcohol consumption in long-term chronic alcohol consumption cases. Hair EtG also provides a reliable diagnostic test to detect heavy drinkers among individuals with alcohol dependence syndrome.

Rapid and simple LC–MS/MS determination of urinary ethyl glucuronide, naltrexone, 6β-naltrexol, chlordiazepoxide, and norchlordiazepoxide for monitoring alcohol abuse

In this study, a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed to detect ethyl glucuronide (EtG), which is a biomarker for monitoring alcohol consumption, and naltrexone (NTX), 6β-naltrexol (6βNTX), chlordiazepoxide (CDP), and norchlordiazepoxide (norCDP), which are analyzed to confirm the presence of medications for alcohol dependence treatment. The protein precipitation method was conducted to rapidly prepare samples. LC–MS/MS analysis was performed in the multiple-reaction monitoring mode. The analytes were separated using a Scherzo SM-C18 (2.0 × 100 mm, 3 µm) column. The calibration ranges were 5–1000 ng/mL for EtG, 6βNTX, CDP, and norCDP, and 1–100 ng/mL for NTX, with the correlation coefficients (r) being ≥ 0.994, and the weighting factor being 1/x2. The lower limit of quantification was 1–5 ng/mL. The method was also validated for precision, accuracy, selectivity, dilution integrity, recovery, matrix effect, and stability. The developed method was successfully applied for the determination of EtG, NTX, 6βNTX, CDP, and norCDP in urine samples obtained from 49 probationers who received alcohol dependence treatment orders. The method developed herein can be used to monitor the drug-based treatment of alcohol abuse and alcohol consumption during the treatment of individuals under probation.