Hair Follicle Testing v Hair Shaft Testing

Posted by TDDA

Hair testing is normally used to determine persistent drug use.

The testing procedure is often incorrectly referred to as hair follicle testing which is in fact a procedure used by investigators to determine someone’s DNA or genetic blueprint.

Hair shaft testing, however, is used to determine compounds and metabolites which have entered the human body via inhalation, ingestion, injection and even through the skin.

Hair shaft testing is the most effective way to detect if for example someone is using illicit drugs on an ongoing basis as part of their lifestyle or if prescribed medications are being used in excess of the recommended dose.

This type of testing can be used for pre-employment testing and helps employers work through due diligence on new hires and contractors that will potentially join the team.

It can also be used by the Courts in custody cases and TDDA has been conducting testing for the Court of Western Australia for several years now.

At TDDA we aim to educate and train, as well as conduct testing, in our journey to help create drug free communities.

If you have specific questions, please call us directly but meanwhile refer below for answers to some commonly asked questions we receive:

Where is the hair taken from?
Either head hair or body hair can be used however the sample cannot be a mixture of both head and body hair.

What steps do you take to identify a person completing a hair test?
They are required to identify themselves with photo identification (ID) e.g. a driver’s licence or passport. The technician checks the ID photo to make sure it is the person that the sample is to be collected from and records the description of the ID and ID number on the chain of custody form (CCF). The ID used is reported with results.

What are the steps between taking a sample and that sample being tested by the laboratory to ensure the sample is not tampered with?

The hair sample is placed into an envelope in front of the donor, sealed with a tamper proof/security seal and then signed by the donor. The security envelope and corresponding signature are checked upon receipt at the lab to ensure they are intact.

Can the accuracy of results be affected if a person bleaches or dyes their hair?

There are currently no known successful commercial adulterants for hair tests and the recommended use of normal hair care products/procedures do not have a significant effect on results.

Are there circumstances where you or the laboratory would refuse to proceed to test a hair sample?

The most common reasons a sample is not analysed include:
• Chain of custody on the sample is not intact, e.g. security seal not on envelope, no identification on sample envelope, names/ID mismatch
• Quantity of sample submitted was not sufficient for analysis
• The hair is identified to not be human hair
• The root end cannot be identified

If a result is under the allowed amount, is it returned as positive or negative?
A result that is below the Omega Laboratories established cut off levels would be reported as Negative

How can a positive result for methamphetamine be followed by a clear test 10 days later?

Hair collected from the head at different time frames can yield differing test results due to factors such as hair growth rates, dormant hair affects and how close to the scalp each specimen was collected.

Can the validity of a hair sample be compromised if the person taking it mistakenly cuts the sample from the wrong end of the hair (not the scalp end) so the results are not from the most recent 3 month period but from an earlier period of time?

It is possible and we have seen photographic evidence of samples taken where the hair was cut well away from the scalp which would result in the test being carried out for an incorrect timeframe. TDDA collection technicians undergo specific hair collection training prior to being able to collect hair samples.

Are you able to comment on how long a substance stays in the body generally?

This varies. An individual’s metabolism, body mass, age, hydration level, physical activity and health conditions all factor in the length of time substances remain in the body.

What is the significance of the different levels of results for a substance mean in terms of usage?

The laboratory is not in a position to determine usage and can only state whether or not the drug and/or metabolite was present in the sample. The amount of drug detected cannot be directly correlated with an amount of drug ingested due to factors such as drug purity, different hair growth rates, age and varying metabolic rates.

When does drug usage need to have taken place prior to testing to be detected in the results? Is this likely to be a range of dates or a particular point in time? 

This is dependent upon the actual growth rate of an individual’s head hair and past drug history.

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