Combined use of fatty acid ethyl esters and ethyl glucuronide in hair for diagnosis of alcohol abuse: interpretation and advantages

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.12.028 Byline: F. Pragst (a), M. Rothe (b), B. Moench (b), M. Hastedt (a), S. Herre (a), D. Simmert (a) Keywords: Alcohol marker; Ethyl glucuronide; Fatty acid ethyl ester; Hair analysis Abstract: In this study the combined use of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for diagnoses of chronically excessive alcohol abuse is investigated at 174 hair samples from driving ability examination, workplace testing and child custody cases for family courts and evaluated with respect to the basics of interpretation. Using the cut-off values of 0.50ng/mg for FAEE and 25pg/mg for EtG, both markers were in agreement in 75% of the cases with 103 negative and 28 positive results and there were 30 cases with FAEE positive and EtG negative and 13 cases with FAEE negative and EtG positive. As the theoretical basis of interpretation, the pharmacokinetics of FAEE and EtG is reviewed for all steps between drinking of ethanol to incorporation in hair with particular attention to relationships between alcohol dose and concentrations in hair. It is shown that the concentrations of both markers are essentially determined by the area under the ethanol concentration in blood vs. time curve AUC.sub.EtOH, despite large inter-individual variations. It is demonstrated by calculation of AUC.sub.EtOH on monthly basis for moderate, risky and heavy drinking that AUC.sub.EtOH increases very strongly in the range between 60 and 120g ethanol per day. This specific feature which is caused by the zero-order elimination of ethanol is a favorable prerequisite for a high discrimination power of the hair testing for alcohol abuse. From the consideration of the different profiles of FAEE and EtG along the hair and in agreement with the literature survey, a standardized hair segment 0-3cm is proposed with cut-off values of 0.5ng/mg for FAEE and 30pg/mg for EtG. This improves also the agreement between FAEE and EtG results in the cases of the present study. A scheme for combined interpretation of FAEE and EtG is proposed which uses the levels of abstinence and the double of the cut-off values as criteria in addition to the cut-off's. Considering the large variations in the relationship between ethanol dose and FAEE and EtG concentrations in hair, the combined use of both parameters strongly increases the accuracy of the diagnosis by mutual confirmation and identification of false positive or false negative results due to biological variations or analytical errors. Author Affiliation: (a) Institute of Legal Medicine, University Hospital Charite, Hittorfstr. 18, 14195 Berlin, Germany (b) Lipidomix GmbH, Berliner Allee 261-269, 13088 Berlin, Germany Article History: Received 12 June 2009; Accepted 22 July 2009