Likewise in cases of drug abuse hair analysis could also be used for the provement of alcohol consumption over a long period (usually 3 month), both in cases of alcoholism (according WHO consumption of more than 60 g alcohol per day over a period of several month) as well as controlling of alcohol abstinent behavior.
Hair analysis is particularly suitable for those whose liver values (GGT, GOT, etc.) are increased by other, non-alcohol disorders. The Determination can also be used as specific marker for the detection of abstinence, used especially for the re-issuance of the driving license.
At a hair length of 3 cm, a period of approximately 3 to 6 months can be evaluated. As an alternative in the absence of head hair resp. too short head hair (minimum: 2 cm) also axillary, breast, leg and pubic hair can be analyzed.
The freed higher fatty acids (myristicine acid, palmitine acid, stearic acid, oleic acid) deriving from the metabolism of fats, reacts in the human body in the presence of ethanol to the corresponding fatty acid ethyl esters (FAEE). These will be deposited on the sebaceous glands in the hair and remains in the hair during the growing period. Since ethanol also naturally occurs as metabolic intermediate, it is also seen in the hair of alcohol abstinent people in a low FAEE-total concentration (aprox. 0.2 ng/mg). In cases of occasional or moderate drinking, the FAEE total concentration increases to 0.3-0.5 ng/mg, while findings above 0.5 ng/mg indicates an excessive, above 1 ng/mg a chronic excessive drinking behaviour. The areas are overlapping.
From the defatted hair (n-heptane), the FAEE are extracted and derivated, enrichend by HS-SPME technique and very sensitive detected by the GC/MS method using deuterated internal standards.
An alternative method is the determination of Ethylglucuronide (EtG) in the hair, but to date it is applied only by a few labs because of the high technical requirement (LC/MS/MS) and the very small amounts of EtG in hair. A disadvantage is the scrubbing of EtG by frequent hair washing, especially in longer hair.
Both methods are suitable to differentiate between "normal drinkers" and excessive drinkers. The cut-off values are recommended by the international Society of Hair Testing, frequently adapted to the current state of research. Currently (06/16/2009) the actual cut-off values are 30 pg/mg for EtG, resp. 0.8 ng/mg for the total FAEE concentration.