Hair analysis

Hair analysis is the chemical analysis of a hair sample. 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.^[1] Its most widely accepted use is in the fields of forensic toxicology and, increasingly, environmental toxicology.^[2][3] Several alternative medicine fields also use various hair analyses for environmental toxicology but these uses are controversial, evolving and not standardized.

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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, benzodiazepines (Valium-type drugs) and amphetamines. ^[4][5] 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 toxics 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 p oroisons linked to behavioral health problems.^[2]

The use of hair alcohol analysis to establish and verify persistent alcohol abusers within the United Kingdom has steadily increased in recent years. As the hair grows, it absorbs special markers called fatty acid ethyl 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. The company that commercialised this in the UK is Trimega Laboratories Limited.

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.

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.

Etg alone is still not reliable.

FAEEs (nanogram = one billionth of a gram) appear in hair in almost one order of magnitude higher than (the relevant order of magnitude of) Etg (picogram = one trillionth of a gram). It has been technically possible to measure FAEEs since 1993, whereas the technique for measuring (the relevant range of) Etg is still in its infancy.

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). So far no systematic investigations in this regard have been carried out for Etg

FAEE concentrations in hair from other body sites can be interpretated in a similar fashion as scalp hair (Hartwig et al., 2003b). Etg: no information available.

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

There are no reliable 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.

Literature Pragst F., Balikova M.A.: State of the art in hair analysis for detection of drugs and alcohol abuse; 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 toxics 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.^[2]

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 CDC to name a few.

A 1999 study on hair concentrations of calcium, iron, and zinc in 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."^[6]

Use in occupational, environmental and alternative medicine

Hair analysis has been used in occupational,^[7] environmental and some branches of alternative medicine as 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,^[8] practitioners screen for toxic exposure and heavy metal poisoning. Some advocates claim that they can also diagnose mineral deficiencies and conditions like autism.^[9] These uses are often controversial, still evolving and not yet broadly standardized.

See also

• Hair analysis (alternative medicine)

References

Bibliography

• Henderson, Gary L., Harkey, Martha R., Jones, Reese T., "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.