Hair analysis is the chemical analysis of a
hairsample. Hair may be considered for retrospective purposes when blood and urine are no longer expected to contain a particular contaminant, typically a year or less. [Eastern Research Group. [http://www.atsdr.cdc.gov/HAC/hair_analysis/5.3.html Section 5, "Choosing the Best Biological Marker."] SUMMARY REPORT, HAIR ANALYSIS PANEL DISCUSSION: EXPLORING THE STATE OF THE SCIENCE. ATDSR. June 12—13, 2001] Its most widely accepted use is in the fields of forensic toxicologyand, increasingly, environmental toxicology. Masters RD. [http://www.dartmouth.edu/~rmasters/Cree/Validity.htm#_ednref4 Validity of Head Hair Analysis and Methods of Assessing Multiple Chemical Sensitivity.] Dartmouth College. accessed 9 Dec 2006.] [ Dartmouth Toxic Metals Research Program. [http://www.dartmouth.edu/~toxmetal/TX.shtml A Metals Primer.] Center for Environmental Health Sciences at Dartmouth. accessed 9 Dec 2006.] Several alternative medicinefields also use various hair analyses for environmental toxicologybut these uses are controversial, evolving and not standardized.
Use in forensic toxicology
Hair analysis can refer to the forensic technique of assessing a number of different characteristics of hairs in order to determine whether they have a common source; for example, comparing hairs found at the scene of the crime with hair samples taken from a suspect.
Hair analysis is also used for the detection of many therapeutic drugs and
recreational drugs, including cocaine, heroin, benzodiazepinesand amphetamines. Welch, M.J., Sniegoski, L.T., Allgood, C.C., and Habram, M. Hair analysis for drugs of abuse: Evaluation of analytical methods, environmental issues, and development of reference materials. J Anal Toxicol 17(7):389-398, 1993.] [Balikova, Marie, [http://publib.upol.cz/~obd/fulltext/Biomed/2005/2/199.pdf "Hair Analysis for Drugs of Abuse: Plausibility of Interpretation"] , Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2005, 149(2):199–207.] In this context, it has been reliably used to determine compliance with therapeutic drug regimes or to check the accuracy of a witness statement that an illicit drug has not been taken. Hair testing is an increasingly common method of assessment in substance misuse, particularly in legal proceedings, or in any situation where a subject may have decided not to tell the entire truth about his or her substance-using history.
Hair Alcohol Testing
Analysis of hair samples has many advantages as a preliminary screening method for the presence of toxic substances deleterious to health after exposures in air, dust, sediment, soil and water, food and toxins in the environment. The advantages of hair analysis include the non-invasiveness, low cost and the ability to measure a large number of, potentially interacting, toxic and biologically essential elements. Hence, head hair analysis is now increasingly being used as a preliminary test to see whether individuals have absorbed poisons linked to behavioral health problems.
The use of hair alcohol analysis to establish and verify persistent alcohol abusers within the
United Kingdomhas steadily increased in recent years. As the hair grows, it absorbs markers called fatty acidethyl esters (FAEE’s) and ethyl glucuronide (EtG) into its structure, which remain in the hair indefinitely. These markers are only produced when there is alcohol in the bloodstream, such that the more markers there are, the more alcohol you have consumed.
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
ethanolmetabolism. The main part of alcohol is oxidized in the human body. This means it is absorbed 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. For EtG detection, more sensitive testing can detect picograms (one picogram equals 0.001 nanograms).
However there is one major difference between most drugs and alcohol metabolites (FAEE) in the way in which they enter into the hair: on the one hand like other drugs FAEEs enter into the hair via the ceratinocytes, 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 millimeters per day on the skin surface, but also the more mature hair growth, providing it with a protective layer of fat.
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. [http://books.google.co.uk/books?id=IBBq180lUEAC&pg=PA305&lpg=PA305&dq=etg+detection+hair++first&source=web&ots=bj_9z-_yJx&sig=X0GVgChngAZeCO4Id4S8P1siyzw&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPP1,M1 "Analytical And Practical Aspects of Drug Testing in Hair, By Pascal Kintz, 2006"] ]
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 (surprisingly) 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).
Extensive studies involving over 1000 donors have been carried out since 2000. These have enabled us to establish reliable reference ranges for FAEEs with respect to drinking habits of the various groups: non-drinkers < 0,4 ng/mg Excessive drinkers > 1ng/mg. Such practices however, may be provide disputable results given that to define an individual as an 'excessive drinker' this would need to define a specific alcohol intake [in units] . Since the way an individual metabolises alcohol varies from person to person, the same quantity of alcohol in units would have varying effects from person to person. It is also not scientifically possible to equate a level of metabolite detected in an individual to a quantity of alcohol as a result of individual differences in metabolism.
There are similar reference ranges for Etg from comprehensive studies. Further investigations are in progress to examine the applicability of the method in practice of the detection of alcohol abuse.
LiteraturePragst F., Balikova M.A.: State of the art in hair analysis for detection of drugs and alcoholabuse; Clinica Chimic Acta 370 2006 17-49.
Auwärter V.: Fettsäureethylester als Marker exzessiven Alkoholkonsums – Analytische Bestimmung im Haar und in Hautoberflächenlipiden mittels Headspace-Festphasenmikroextraktion und Gaschromatographie-Massenspektrometrie. Dissertation Humboldt-Universität Berlin 2006.
Pragst F., Auwärter V., Kiessling B., Dyes C.: Wipe-test and patch-test ror alcohol misuse based on the concentration ratio of fatty acid ethyl esters and squalen CFAEE/CSQ in skin surface lipids. Forensic Sci Int 2004; 143:77-86.
Use in environmental toxicology
Analysis of hair samples has many advantages as a preliminary screening method for the presence of toxic substances deleterious to health after exposures in air, dust, sediment, soil and water, food and toxins in the environment. The advantages of hair analysis include the non-invasiveness, low cost and the ability to measure a large number of, potentially interacting, toxic and biologically essential elements. "Hence, head hair analysis is now increasingly being used as a preliminary test to see whether individuals have absorbed poisons linked to behavioral or health problems."
Use in detection of long term elemental effects
There appears to be genuine validity to the use of hair analysis in the measurement of life-long, or long-term heavy metal burden, if not the measurement of general elemental analysis. Several interesting studies including the analysis of
Ludwig van Beethoven's hair have been conducted in conjunction with the National Institutes of Health, and Centers for Disease Control and Preventionto name a few.
A 1999 study on hair concentrations of
calcium, iron, and zincin pregnant women and effects of supplementation, it was concluded that "From the analyses, it was clear that hair concentrations of Ca, Fe, and Zn could reflect the effects of supplementation...Finally, it could be concluded that mineral element deficiencies might be convalesced by adequate compensations of mineral element nutrients." [ [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=10468164&query_hl=39&itool=pubmed_docsum PMID: 10468164 Hair concentrations of calcium, iron, and zinc in pregnant women and effects of supplementation.] Leung PL, Huang HM, Sun DZ, Zhu MG. "Biol Trace Elem Res." 1999 Sep;69(3):269-82.]
Use in occupational, environmental and alternative medicine
Hair analysis has been used in occupational, [ Niculescu T, Dumitru R, Botha V, Alexandrescu R, Manolescu N. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6824602&dopt=Abstract Relationship between the lead concentration in hair and occupational exposure.] Br J Ind Med. 1983 Feb;40(1):67-70.] environmental and some branches of
alternative medicineas a method of investigation to assist screening and/or diagnosis. The hair is sampled, processed and analyzed, studying the levels of mineral and metals in the hair sample. Using the results, as part of a proper examination or test protocol,Bass DA, Hickok D, Quig D, Urek K. [http://www.thorne.com/pdf/journal/6-5/trace_element_analysis.pdf Trace element analysis in hair: factors determining accuracy, precision, and reliability - Statistical Data Included.] Altern Med Review 2001;6(5):472-481.] practitioners screen for toxic exposure and heavy metal poisoning. Some advocates claim that they can also diagnose mineral deficienciesand that people with autismhave unusual hair mineral contents.Lathe, Richard, and Michael Le Page. "Toxic metal clue to autism: a study has revealed startling differences in mercury levels in the hair of autistic and normal children. (This Week)." "New Scientist" 178.2400 (June 21, 2003): 4(2).] These uses are often controversial, still evolving and not yet broadly standardized.
Hair analysis (alternative medicine)
*Henderson, Gary L., Harkey, Martha R., Jones, Reese T., [http://www.druglibrary.org/schaffer/cocaine/cokehair.htm "Analysis of Hair for Cocaine"] , in (eds. Edward. J. Cone, Ph.D., Michael. J. Welch, Ph.D., and M. Beth Grigson Babecki, M.A.), "Hair Testing for Drugs of Abuse: International Research on Standards and Technology", 1995, p. 91-120. NIH Publication No. 95-3727.
* [http://www.criminology.fsu.edu/journal/mcbay2.html Article: Hair Drug Testing Bibliography]
* [http://altmedicine.about.com/cs/govtregulation/a/HairTests.htm Study Questions Reliability of Hair Tests]
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