Monitoring of the alcohol biomarkers PEth, CDT and EtG/EtS in an outpatient treatment setting.

AIMS

To compare the sensitivity of whole blood phosphatidylethanol (PEth) with serum carbohydrate-deficient transferrin (CDT) as biomarkers of current regular alcohol consumption, during outpatient treatment for alcohol-related problems. Urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS), and clinical assessment, were used as complementary estimates of relapse to drinking.

METHODS

Biomarker results for 29 men and 11 women (aged 20-73 years) undergoing voluntary outpatient treatment for harmful alcohol use or dependence were utilized for this evaluation. In connection with visits to the unit, blood and/or urine were sampled for measurement of PEth, EtG and EtS (by liquid chromatography-mass spectrometry), and CDT (%disialotransferrin, by high-pressure liquid chromatography).

RESULTS

The comparison included 326 whole blood, 319 serum (1-82 samples/patient) and 654 urine samples (1-178 samples/patient) collected over ~2 years. At the initial assessment, the total PEth value ranged between 0 and 16.5 µmol/l (mean 2.6) with 70% being above the quantification limit (0.1 µmol/l) and 55% above the reference interval (0.7 µmol/l). Initial CDT values were 0.87-6.9% (mean 2.1) with 35% above the applied reference interval (1.7%). At the final sampling (treatment period up to 21 months), the total PEth value had decreased to 0-5.9 µmol/l (mean 0.6; P = 0.0004) and CDT to 0.87-3.3% (mean 1.3; P = 0.0030). Relapses were detected by PEth alone (43% of cases), by PEth and CDT (38%) and the remainder by EtG/EtS.

CONCLUSION

PEth was the most sensitive biomarker of current regular alcohol consumption. PEth-16:0/18:1, usually being the major subform, was as sensitive as total PEth. PEth, CDT and EtG/EtS are useful complementary tools for objective identification of current drinking and relapse detection.