Alcohol
In contrast to other drugs consumed, alcohol is not deposited directly in the hair. For this reason the investigation procedure looks for direct products of ethanol metabolism. The main part of alcohol is oxidized in the human body. This means it is released as water and carbon dioxide. One part of the alcohol reacts with fatty acids to produce esters. The sum of the concentrations of four of these fatty acid ethyl esters (FAEEs: ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) are used as indicators of the alcohol consumption. The amounts found in hair are measured in nanograms (one nanogram equals only one billionth of a gram), however with the benefit of modern technology, it is possible to detect such small amounts. In the detection of ethyl glucuronide, or EtG, testing can detect amounts in picograms (one picogram equals 0.001 nanograms).
However there is one major difference between most drugs and alcohol metabolites in the way in which they enter into the hair: on the one hand like other drugs FAEEs enter into the hair via the keratinocytes, the cells responsible for hair growth. These cells form the hair in the root and then grow through the skin surface taking any substances with them. On the other hand the sebaceous glands produce FAEEs in the scalp and these migrate together with the sebum along the hair shaft (Auwärter et al., 2001, Pragst et al., 2004). So these glands lubricate not only the part of the hair that is just growing at 0.3 mm per day on the skin surface, but also the more mature hair growth, providing it with a protective layer of fat.
FAEEs (nanogram = one billionth of a gram) appear in hair in almost one order of magnitude lower than (the relevant order of magnitude of) EtG (picogram = one trillionth of a gram). It has been technically possible to measure FAEEs since 1993, and the first study reporting the detection of EtG in hair was done by Sachs in 1993.
In practice, most hair which is sent for analysis has been cosmetically treated in some way (bleached, permed etc.). It has been proven that FAEEs are not significantly affected by such treatments (Hartwig et al., 2003a). FAEE concentrations in hair from other body sites can be interpreted in a similar fashion as scalp hair (Hartwig et al., 2003b).
Hair Alcohol Testing was first commercialised in the UK by Trimega Laboratories.
Read more about this topic: Drug Test, Types, Hair Testing
Famous quotes containing the word alcohol:
“Two great European narcotics, alcohol and Christianity.”
—Friedrich Nietzsche (1844–1900)
“Some parents feel that if they introduce their children to alcohol gradually in the home environment, the children will learn to use alcohol in moderation. I’m not sure that’s such a good idea. First of all, alcohol is not healthy for the growing child. Second, introducing alcohol to a child suggests that you condone drinking—even to the point where you want to teach your child how to drink.”
—Lawrence Balter (20th century)
“No power on earth or above the bottomless pit has such influence to terrorize and make cowards of men as the liquor power. Satan could not have fallen on a more potent instrument with which to thrall the world. Alcohol is king!”
—Eliza “Mother” Stewart (1816–c. 1908)