Phosphatidylethanol in patients with liver diseases of different etiologies: Analysis of six homologues and comparison with other alcohol markers.

BACKGROUND AND AIMS: Phosphatidylethanol (PEth) is a direct alcohol biomarker. Aim of the study was to evaluate the performance of six homologues of PEth in comparison to other alcohol markers in patients with liver diseases. METHODS: The study included 234 patients with liver disease, who gave statements about alcohol consumption during the three months prior to the doctor's appointment. Ethylglucuronide in urine (uEtG) and in hair (hEtG) and carbohydrate-deficient transferrin (CDT) were analyzed in addition to PEth. RESULTS: Of all patients 47% stated to have drunk alcohol during the past three months. UEtG, hEtG and CDT showed a sensitivity of 29% and a specificity of 92% together for ingestion of at least two standard drinks (24 g) per week. With PEth 16:0/18:1 in addition, sensitivity increased to 59%. For consumption in the last week uEtG's sensitivity and specificity was 28% and 100%, respectively. PEth's was 75% and 93%. When looking at patients who consumed at least two standard drinks per week during the past three months and of which a hair sample could be obtained, hEtG's sensitivity was 37% and specificity 90%. PEth had a sensitivity of 53% and specificity of 100%. Quotients of PEth 16:0/18:1 with 16:0/18:2, 16:0/20:4 and 18:0/18:2 were smaller when alcohol had been consumed more recently. CONCLUSION: Despite the rather poor overall sensitivity of alcohol biomarkers in this study, PEth showed best sensitivity for all time periods of alcohol consumption.

Impaired diagnostic accuracy of hair ethyl glucuronide testing in patients with renal dysfunction.

The impact of renal impairment and hemodialysis on ethyl glucuronide concentrations in hair (hEtG) is not well known. Here, hEtG levels were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in patients presenting to the transplant outpatient clinic and compared with the self-reported alcohol consumption in an anonymous validated questionnaire. Estimated daily alcohol intake (EDI) was calculated. A total of 94 patients with varying renal function (Glomerular filtration rate (GFR) > 60 mL/min: group 1 (n = 47); GFR 30-60 ml/min: group 2 (n = 29); GFR < 30 mL/min: group 3 (n = 18)) were included in the study. Fifteen of 18 (83.3%) patients in group 3 were on dialysis. Altogether, hEtG tested positive (> 5 pg/mg) in 25.5% (n = 24) of patients, while 36.2% (n = 34) and 14.9% (n = 14) of patients reported any or regular (> 10 g/d) alcohol consumption, respectively. The median hEtG concentration of positive samples was much higher in patients in group 3 with advanced renal dysfunction or on dialysis than in patients in group 1 or 2 (group 1, 2, 3 dialysis patients: 74, 52, 145 and 155 pg/mg, respectively), although they consumed on average much less alcohol per day (median EDI group 1, 2, 3, dialysis patients: 16, 17, 3 and 3 g/d, respectively). Also, there was a significant correlation between the hEtG concentration and EDI for patients in group 1 (ρ = 0.84; p = 0.01), but not for patients in group 2 (ρ = -0.35, p = 0.39) or 3 (ρ = 0.02, p = 0.96). Furthermore, the ability of hEtG to correctly identify abstainers as such was lower for patients with advanced renal dysfunction than for the remaining patients (specificity for group 1, 2, 3: 92%, 87%, 82%, respectively). So, monitoring hEtG concentration was less reliable in patients with advanced renal dysfunction or on hemodialysis and by far overestimated the amount of alcohol consumed.