hair drug testing work

How does hair drug testing work?

Hair drug testing is the scientific analysis of chemical components present in strand samples of hair. It is used to detect the presence of a number of substances to determine what a person has ingested or used and is considered to be one of the most infallible methods of gaining an accurate picture.

This process is authorised or undertaken by a number of organisations such as the Police, solicitors’ firms, hospitals and sports governing bodies in cases where there is suspicion of substance misuse and in criminal cases it is also used to analyse hair samples from the victim or those remanded in custody. Forensic hair analysis is often required in sexual assault cases where a ‘date rape’ drug such as Rohypnol may have been involved.

A wide range of substances can be detected from a single hair sample, from over the counter medicines such as Codeine through to Class-A drugs such as LSD, heroin and cocaine. A hair sample provides a more reliable analysis because the traces of substances can remain within the hair strand for three months. However, it can take up to two weeks for substances to become present in hair, so unlike urine or saliva samples, which can provide immediate results if taken at the time of incident, hair drug testing is not effective in this respect.

Ingested substances are absorbed into the blood stream and become present in the hair follicle where they will then remain present in the hair shaft as it grows. This means that a single hair will contain a substantial record of drugs absorbed over a period of months. Hair grows at around 1cm per month so depending on the length of hair sample used a picture can be built up of the various substances ingested at different stages in time as well as showing trends in usage.

Further advantages of hair strand testing are that it is much easier to obtain a sample of hair than other types of bodily sample and it cannot be manipulated. Although some processes such as dyeing hair may affect the analysis, hair sampling is still an extremely reliable method. Furthermore, this process will not be as time-dependent as blood or urine samples in which trace elements of drugs will dissipate far more quickly by comparison.

Different drugs produce different chemical reactions within the body and these can be detected by specific tests. Therefore a number of different tests can be carried out on a hair sample to identify different substances.

Click on Lextox Drug Testing Experts to know more about it.

Obviously a way to try and defeat a hair drugs test would be for the person in question to shave their head completely! However, the timing of this may be likely to raise suspicion and clearly this is a drastic move which would not be appropriate for many people. If someone resorted to this in order to try avoiding a hair drugs test, the advantage would be that hair grows back very slowly and this may buy them some valuable time. However, samples of hair from the chest and face have also been used but they cannot be tested in quite the same way, and typically this will only apply to men!

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