Hair Analysis a Useful but Not Foolproof Forensic Tool
by Derek Gilna
Richard Paul, a Bournemouth University, England, chemistry professor and specialist in toxicological hair analysis, maintains that although the relatively new technology can be useful, it is far from foolproof. He cautions that even though the High Court of the United Kingdom has accepted the results of hair analysis as accurate in some cases, tests can sometimes be skewed by something as commonly used as hair spray.
Unlike breathalyzers or blood tests, which give what essentially is a snapshot of the individual’s drug and alcohol levels for a period of time as short as several hours or perhaps a few days, human hair “stores” a record of all substances used over a period of months and might even show if you are stressed. And, Paul added, the level of accuracy has increased in recent years.
The hair analysis process first came to prominence as a forensic tool in 2008, where a mother who had been banned from consuming alcohol for a year in a child custody dispute had to produce a hair sample, which technicians claimed showed that she had, in fact, consumed alcohol during that period. The High Court, after reviewing the data, threw out the test results, deeming them unreliable.
Over 10 years later, a hair analysis case again came before the High Court, but this time the court accepted the findings. Much as DNA testing has evolved and become more accurate, hair analysis also has become more reliable. It is now widely accepted that drugs remain trapped in human hair, offering clues to possible substance problems and other medical issues.
However, Paul says some “factors ... affect the hair concentration of certain chemicals produced when the body processes alcohol (metabolites and) hair sprays and waxes can greatly increase the level of alcohol metabolites found in hair, giving a false positive result in an alcohol test.” Nonetheless, he said, “scientists ... can ... mitigate against them, and (some alcohol metabolites are) not affected by hair sprays and waxes and so is a better target to test when someone uses cosmetic products.”
Also, he said hair analysis is not only useful in diagnosing drug and alcohol use, but has also proved useful in determining whether an individual is under stress so that steps can be taken to mitigate this potential long-term health issue.
Source: forensics.com
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