DRUGS IN HAIR
Today, thanks to many scientific advances, toxicology tests can be carried out on different biological samples, such as blood, saliva, sweat, urine and hair, which allow us to find out whether a person has taken drugs, when and for how long. The test of choice is certainly the analysis of scalp and body hair: it has long been known that drugs and their metabolites are incorporated into the keratin of the hair during metabolism and remain there for long periods. Since hair grows on average 1 cm a month, analysing known segments makes it possible to trace the period of use. As well as being one of the most reliable tests, since it uses the most advanced diagnostic technologies, it minimises the possibility of tampering with the sample and allows non-invasive collection with full respect for the person’s privacy. The test is now widely used for medico-legal assessments such as driving licence medical boards, adoption cases or firearms licences, and by parents who want to check on their children
Segmental analysis
Segmental analysis is a detailed test which, unlike the previous one, is carried out by cutting the collected lock of hair into sections. Each centimetre of hair can be analysed, as each centimetre corresponds roughly to a period of one month.
This means that, for example, with a lock 3 cm long, analysis of the first centimetre (the one closest to the scalp) shows any drugs taken by the person in the last month; analysis of the second centimetre shows the situation two months ago, and analysis of the third centimetre the situation three months ago.
Segmental analysis also allows alternate testing: instead of examining every available centimetre, some centimetres chosen by the client are left out.
For example: I have a lock of hair 10 cm long. I want to know whether the person the hair belongs to took drugs 10 months ago, whether they are still taking them, and whether, over the last 10 months, their use has been regular or occasional.
These questions can be answered by choosing, for example, to analyse the first and tenth centimetres (the closest to and furthest from the scalp) to check first the situation ten months ago and the current one, and then continuing with the eighth, sixth, fourth and second centimetres, so that it is possible to confirm or rule out, even without examining all 10 centimetres, that the person has used drugs with some continuity.
Quantitative analysis
As well as the type of drug taken, this shows how much of it is present in the sample
Types of test available
Basic test
This is the most widely used test internationally and detects use of the four main classes of drugs over the last three months (and beyond):
– amphetamine group: amphetamine, methamphetamine, MDMA or ecstasy, MDA
– cocaine and its metabolites: cocaine, benzoylecgonine and other metabolites, “crack”
– opiate group: codeine, morphine, heroin metabolites
– cannabinoids: marijuana, THC-COOH, hashish
The test can detect drugs even at minimal levels and is particularly useful as a preventive check for workers in high-risk jobs and for drivers who are required to have a hair test to get their driving licence back, so that they can be sure of passing the official test.
Results are available within 7 working days of receiving the sample.
Exceptionally, at the same price as the basic test above.
Frequently asked questions
What period of time does a standard test cover?
A standard test covers a period of about 90 days, since the 3.9 cm of the sample closest to the scalp is analysed.
How far back can the hair test go?
The test can go back months or even years, depending on the length of the donor’s hair.
How fast does hair grow?
Studies show that hair grows on average about 1.3 cm a month, with an individual variation of ± 0.2 cm.
How much hair is needed for a test?
A standard test with GC/MS confirmation requires about 90-120 hairs (about the thickness of a pencil) 3.9 cm long. The range reflects the different thickness of different types of hair. If the hair is shorter, more hair will be needed to detect any drugs, but the period of use covered will be limited to a few weeks.
If further analyses are added to the basic test, more hair is needed: at least 150 hairs.
How long after use can a drug or other substance be detected in hair?
It takes about 4-5 days from the time of use for the hair to grow above the scalp.
Can the test be done on people with little or no hair?
Hair can be collected from different areas of the scalp, but body hair from other parts of the body can also be used. In this case the period covered by the test cannot be determined precisely, because body hair grows differently from scalp hair.
Can hair collected from a brush be used?
Yes; in this case the test will show whether the sample contains metabolites of drugs or other substances, but it will not be possible to determine when they were used.
Can a mixed sample of scalp and body hair be provided?
No, because scalp and body hair grow in different ways and at different rates