Legal Hair Drug Test
An Introduction to Hair Drug Testing
A hair strand drug test can assess your client’s history of drug consumption over a period of time up to one year. The period of detection is determined by the length of hair.
On average, hair grows at a rate of 1cm per month. Therefore, if a client has 6cm of hair, we can assess a 6-month period of consumption.
The court will often request assessment of a client’s pattern of consumption (whether consumption of a particular substance has increased or decreased). By segmenting the hair into monthly sections, we can provide a more comprehensive assessment of the pattern of change.
DNA Legal's hair strand drug testing works by looking for the metabolites (chemical signatures) of the drug that are absorbed into the blood and deposited into the hair as a result of drug consumption.
For even more information, read our hair drug testing FAQs
Range of drugs that can be tested
Legal professionals can select the individual drugs that they test their client for or request a test for a common set of drugs. In the UK there are 9 common drugs of abuse tested:
- Cocaine (including crack)
- Opiates (including heroin)
- Methamphetamines (including ecstasy)
- Mephedrone (aka methedrone or M-CAT)
However, we can test for an extremely extensive range of substances.
To enquire about our comprehensive library, please call our team of experts who can advise on a case-by-case basis.
Designer Drugs & Legal Highs
Since 2005, the UK has seen hundreds of new illicit substances enter the drug market.
DNA Legal continually reassess and update our testable library to ensure we are prepared to facilitate any request – and can test for over 2,000 substances.
New Psychoactive Substances – such as ‘Spice’ – are frequently modified and therefore hundreds of molecular variants can now be found on the market. This presents a potential problem in terms of investigating their consumption, with most toxicology testing providers being able to identify only 10 Spice variants.
At DNA Legal, we can test for over 160 variants of Spice, and over 300 other New Psychoactive Substances. In addition, we have developed comprehensive panel screening for other abused substances, including:
- Prescription drugs
- Antidepressants, neuroleptics and anxiolytics
The importance of segmentation
Segmentation is an important aspect of hair strand drug testing – but when should it be used?
If your client has previously taken drugs, it is important to perform a month-by-month segmentational analysis in order to establish the pattern of change. This permits separation of a potentially positive overview into a more accurate breakdown of monthly consumption.
There is no need to segment if your client has not taken drugs, as a standard overview is all that is needed.
Passive exposure and contamination
Not every hair drug test is the same. Many firms test just a small number of metabolites for each drug group and some do not test any. This means it is very difficult to identify if the drugs have been consumed by the client or appear as a result of passive exposure. In general, the more detailed the hair test and the larger the number of metabolites tested the more accurate the result.
To further support this, DNA Legal carry out an extended wash process to ensure all traces of contamination are removed from the hair.
Uniquely, we always test the washes to ensure result of the hair test is not due to contamination.
At DNA Legal, distinguishing between contamination and consumption is key to our analytical process.
How do hair drug tests work?
Hair strand drug testing analyses hair samples to assess a history of drug consumption. Hair samples are sent to our laboratory to be examined for both substances and metabolites – a primary indicator of usage with in a specific period of time, rather than contamination.
DNA Legal are able to define whether a client has only been in an environment with drugs, e.g. where cannabis has been smoked, or if they have consumed the substance themselves. Hair drug testing can accurately identify past drug patterns up to 12 months, dependent on the client's hair length; 1cm of hair can reflect one month of drug use.
How much hair is needed for a drug test?
One of the questions most commonly asked is ‘how many strands of hair are needed for testing?’. This can vary depending on hair thickness, but a single sample will take approximately 200 hairs – about the width of a pencil. Multiple samples may be needed depending on the testing required.
Head hair grows on average 1cm a month; the length of hair will determine the length of time we can detect drug use for.
What factors can affect a hair drug test?
Chemically treated hair
Chemical treatment of hair can affect a hair strand test. However, we account for chemical treatment and advise in these circumstances. We can also perform testing of alternative samples, such as fingernails – which are not susceptible to such treatments.
Hair colour and texture
Scientific research indicates that drug metabolites attach to melanin in hair. This means that more of a given substance can be sequestered by darker hair, than by lighter hair.
We take these factors into account during our expert toxicological assessments and reports.