Legal Hair Drug Test

Hair Drug testing with absolute accuracy

Hair Drug Testing

Hair Drug Testing

Legal Hair Drug Test

An Introduction to Hair Drug Testing

Hair drug testing can show your client’s history of drug use over a period of time covering up to one year, and in some cases longer. The length of time is determined by the length of hair.

On average hair grows at 1cm per month therefore if your client has 6cm of hair they can be tested for drugs covering a 6 month history. It is common that the court are seeking to determine that a known drug user has stopped taking drugs, by cutting the hair into smaller lengths for example 1cm segments, you are provided with a month by month history of drug use. 

DNA Legal's hair drug test 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 ingestion. 

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:

  • Cannabis 
  • Cocaine (including crack) 
  • Opiates (including heroin) 
  • Amphetamines 
  • Methamphetamines (including ecstasy)
  • Benzodiazepines 
  • Methadone 
  • Mephedrone (aka methedrone or M-CAT) 
  • Ketamine 

Hair Drug Testing Options

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Desginer Drugs & Legal Highs

Since 2005 the UK has seen over 254 new drugs come onto the market. For this reasons DNA Legal can now test for over 2,000 drugs. 

Prescription drug abuse has become a serious issue in the UK, and is now being listed as the second most abused drug after alcohol. DNA Legal have therefore developed a hair test that cover 186 drugs in one. We also have specific screens for ; 

  • Legal highs and synthetic cannabis 
  • Designer drugs 
  • Steroids 
  • GHB 
  • Hallucinogenics, antidepressants, neuroleptics and hypnotics 

The importance of segmentation 

Segmentation is an important aspect of hair drug testing – but when should it be used? If your client has ever taken drugs in the past it is important to request a monthly segmented test.

This allows a report to show a decreasing use of drugs over a period of time, distinguishing from showing the whole test with a positive result, which may have been from a previous period of time when the client did use drugs. 

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. 

As a unique service we even test the wash to determine the level of drugs found, once they are close to zero we know the result of the hair test is not due to contamination. 

This takes 3 times as long as just testing the hair and is not common practice in UK labs, but it is something we feel is essential to avoid false positive results. 

How do hair drug tests work?

Hair drug testing analyses a sample of hair for the use of drugs over a selected period of time. Your client’s hair sample is sent to our laboratory to be examined for drug substances and our toxicology experts will look for metabolites; a primary indicator that your client has used drugs within a set period of time.

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 ingested the substance themselves. Hair drug testing can accurately identify past drug patterns from up to 12 months, dependent on the client's hair length; 1cm of hair can reflect one month of drug use.

Before we conduct a hair drug test it is important your client does not cut their hair, dye, bleach or chemically treat their hair, and avoid using hair products containing ethanol or alcohol; these can potentially lead to false positives. 

How much hair is needed for a drug test? 

One of the most common questions asked is ‘how many strands of hair are needed?’. This depends on the thickness of hair, and the types of drugs tested, but usually between 100-200 strands of hair are needed. If your client is having an alcohol test as well as a hair drug test, two hair samples will need to be collected.

This amount of hair is required because hair growth is not constant or consistent; a smaller sample of hair may be from an earlier time period to what is required for testing. A larger amount of hair can help avoid false positive results. Technologies are advancing to require smaller amounts of hair, however, the more hair that is tested the more accurate the result will be. 

Head hair grows on average 1cm a month; the length of hair will determine the length of time we can detect drug use for. The most common test is required to cover 6 months, if a client has less than 6cm of head hair, a combination of head and body hair can be used.

What factors can affect a hair drug test?

Bleached or chemically treated hair
Bleaching hair can remove evidence of drug use, however, this depends on the type of drug used, for example, cannabis is more difficult to detect, and the number of times a person has bleached their hair. If a person bleaches their hair on a regular basis, it is likely that no drugs can be detected. In scenarios similar to this, fingernail testing can be used to detect drug use.

Hair products
Approximately 20% of hair products in the UK may cause false positive results when used on a regular basis, DNA Legal offer alternative testing methods that will achieve a conclusive result.

Hair colour and texture
Studies have shown that drug metabolites attach to the melanin in hair; a client with blonde hair is likely to show a lower level of drug use than a client with dark brown hair.