Should laboratory cut-off levels for drugs of abuse in hair and nail testing be abolished?
Should laboratory cut-off levels for drugs of abuse in hair and nail testing be abolished?
The Society of Hair Testing (SoHT) laboratory cut-off levels were established 30 years ago following rudimentary research and when lab equipment was in its infancy. Given the grave consequences of wrong decisions regarding a child’s future, and previous calls from the Judiciary to scrap laboratory cut-off levels, FTS firmly believes it is time for the family law sector and the Judiciary to demand that laboratory cut-off levels be abolished. All laboratories should be instructed to report all findings, thereby providing expert forensic investigations that supports decisions based on the balance of probabilities.
We can trace the forensic hair analysis all the way back to 1855 when it was used as part of the murder trial of John Browning. At this time, it was not possible to examine hair for organic substances such as drugs because analytical methods were not sensitive enough. During the 1980s, developments of specific assay methods such as gas chromatography/mass spectrometry enabled the analysis of organic substances trapped in the hair. In the late 1990s hair strand testing started to be introduced into care proceedings as evidence.
Hair presented a new challenge because it existed outside the body, unlike blood, urine, and oral fluids, and is exposed to environmental contaminants. So how would those interpreting the laboratory analysis know whether the results showed actual drug use or passive exposure? Back in the 1990s the laboratory equipment and methods were not sensitive enough to establish actual use (and levels of use) versus passive exposure.
Around 1995, limited and uncontrolled studies were carried out on unsegmented hair. These revealed that certain thresholds were exceeded when the donor was a regular user. Conversely, when the donor was exposed passively to drugs in the environment, the results would fall below this threshold. Following this rudimentary study, the Society of Hair Testing (SoHT) laboratory reporting cut-off levels were established. So, above the SoHT threshold, the donor would be deemed a chronic substance abuser, below the threshold, no drug use.
Two things have simultaneously happened during these 30 years since the SoHT laboratory cut-off levels were introduced; Laboratory techniques and scientific understanding of hair strand analysis has progressed immensely. People have started to bleach, dye, heat-treat, straighten, and style their hair much more than they did three decades ago.
Every laboratory knows how all these factors can radically affect the level of drugs in someone’s hair. The industry also knows from published and peer reviewed studies such as Rollins, D (2004), “Role of Melanin in Drug Incorporation into Hair”, that those with black hair (more melanin) could have up to 10 times more of the same amount of drug as opposed to someone with blonde or ginger hair.
Moreover, there are now many more laboratories than existed 30 years ago. They all have different methods of hair collection, sample preparation, sample analysis and equipment. Therefore, each set of results from each laboratory on any given day will report various levels of drug. The United Kingdom Accreditation Service (UKAS) External Quality Assessment Scheme’s (EQAS) send all accredited laboratories “blind” homogenised hair samples to analyse, and their published results clearly show marked differences in all laboratory results.
Therefore, to apply the SoHT cut-off levels, developed 30 years ago to these 21st Century laboratories, with all their different methodologies, and with donors manipulating their hair so much makes no sense at all. They are not appropriate for complex care cases and family legal proceedings where decisions can have immeasurable effects on children and families.
In family courts, evidence must achieve a standard of proof described as “balance of probabilities.” Recent high-profile court of appeal cases have exposed that the incumbent process when relying on the use of laboratory cut-off levels, does not achieve this in all cases (Re H (A Child – Hair Strand Testing) [2017] EWFC 64). Using this binary approach to report drug test results, in isolation of forensic investigations, is leading to the gravest injustices imaginable; the wrongful removal of a child from their parents or leaving a child to harm or suffering.
FTS (Forensic Testing Service) believes now is the time for change.
You can read our latest article in the Newcastle Law Society Magazine – Newcastle News
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