Hair Testing FAQ

If the donor has dyed or bleached their hair is it still worth doing a hair test? 

Yes, hair drug testing on a donor who has dyed or bleached their hair may still be worth your while. Any chemical treatment such as hair dye, bleach, chemical straightening and permanent waves can damage the hair.  This damage may lead to some of any drugs that may be present, being leached out from the hair, therefore treated hair may hold less drug than if the hair had not been treated.  As a result, it is possible that low or single use of any drugs may not be detected.  More frequent use of drugs can still be detected but the concentration found may be less than that detected in untreated hair.

Is there a difference between hair that was dyed a long time ago as opposed to more recent dyeing in terms of the results?

There is a difference in that the hair dyed a long time ago will be further down the shaft and possibly exposed to more environmental damage such as sun damage.  Anything that damages hair will allow drugs and metabolites to leach out.  Ideally, hair drug testing works best on undyed hair.

Is it true that a donor can still have the occasional use of drugs during the period analysed and for this not to show up on in the hair test?

It is possible that low or single use of drugs may be at a level that is below detection by the laboratory. Different drugs and their metabolites bind to the hair with different strengths, so some will leach out more easily than others.  Month-by-month analysis is the more sensitive test if you are looking to detect occasional use.

Does hair drug testing show levels? 

Yes. The quantity or level of drugs detected in the hair sample, are listed with both the Certificate of Analysis and the Expert Witness Report.  Positive results are reported in nanogram of analyte per milligram of hair (ng/mg).  However, it is not possible to pinpoint the actual day of ingestion, nor is it possible to define the dose ingested from the level detected in the hair.

How much hair is needed for analysis?

We collect 2 or 3 locks of hair depending on whether the analysis is for drugs (2 locks) or drugs and alcohol (3 locks). Each lock of hair is approximately 50-100 strands of hair. The laboratory keeps 1 lock of hair in reserve in case additional testing is required.

Can the hair from my daughter’s hair brush be collected and analysed?

No. We provide a chain of custody collection and testing service. This requires consent from the donor (person providing the hair sample).

Can a hair test be avoided if I shave my head?

Head hair is the preferred sample, however body hair can also be used for drug and alcohol testing. Our collectors can collect samples from beard, underarm and chest hair. Pubic hair must be collected by a GP.

I have not used any cocaine in the last 3 months but my hair test showed I had used during that period. How is that possible?

When people stop taking drugs, drug levels quickly drop but these levels can remain detectable for some months because of the proportion of hair in the resting phase. This phase of hair is not growing but does contain traces of drug from previous use. It can take some months for all traces of drugs to be eliminated from the hair after cessation of use.

Many of my friends smoke dope while I’m around them. Could my hair test be falsely positive for cannabis because of passive smoking?

There may be a low level of cannabis (THC) present in your hair sample which would indicate an association with cannabis. However, when testing hair samples for cannabis use, the laboratory looks for the presence of both the parent drug (THC) and the metabolite (11-nor-delta9-THC-carboxylic acid). The presence of the metabolite confirms drug use and excludes environmental contamination. The presence of THC in isolation cannot be regarded as an absolute indicator of cannabis use.

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