Mobile Drug Testing: How Long Do Drugs Stay in Your System?


With mobile drug testing (MDT) is increasingly common across Australian roads, it is more than likely that at some point you will be tested for illicit substances.

MDT has been a controversial issue with some members of parliament, most noticeably MP David Shoebridge who petitioned the police to abandon the MDT, calling their system flawed and unfair to drivers who had consumed the illegal substances days before losing their license, which is due to the length that drug remnants remain in the human body.

The results of a MDT can be reliant on the type of test, the person tested, the substance itself and the time frame that the test is performed.

With the war on recreational substances always waging, it is crucial to know where you stand when it comes down the facts and what exactly goes on during an MDT test.

How does a mobile drug test work?

When pulled over for a MDT, you will be asked to provide your license and will be breath tested, if the police find it necessary they will then ask you to wipe an absorbent swab stick that tests for illegal substances across your tongue and then wait few minutes for those results to appear.

If the test is a positive reading, you will be banned from driving for 24 hours and the officers will then escort you to either a roadside MDT van or a nearby station for a more accurate testing.
This is done by taking a sample of your saliva which will then be sent to a laboratory, and if confirmed, an offence of driving under the influence of illegal drugs will be charged.

It is important to co-operate reasonably with the police, as there are penalties in place for the refusal to provide test samples.

What drugs does a mobile drug test detect?

An MDT tests for the 4 most common illegal drugs, known as:

• Speed
• Ecstasy
• Cocaine

The reason that other substances are not screened in the process of an MDT is due to the difficulty in getting a ‘significant level’ so that it is chargeable in court and not easily dismissed as a false positive.

How often do the police do a drug test?

NSW is well known to have one of the largest MDT programs, with 100,000 tests said to be planned for 2017 and 2018.

Police can combine a random breath testing (RBT) with a MDT if they think it is necessary at any time when pulling a driver over.

How long do Drugs stay in my system?

Most substances take up to 48 hours to leave the body, though a combination of drugs can take longer periods.

Drugs will metabolize differently for every person with factors such as weight, hydration, the potency of the illegal substance and how often it was used being the main game changers.

Metabolism is the process the body uses to get rid of any substances such as drugs, though even if the substance is excreted from the body there can be other traces left by the metabolism process itself.

What are the methods used for drug testing?

A unusual factor such as the method used for drug testing can also yield different results depending on the substance that is used and the time frame.

These methods are explained further below:

Saliva testing – A saliva test can reveal when the active ingredient of an illicit substance is in the system and will indicate recent use.
Cannabis being detected after 12 hours is unlikely and other substances can be in most cases be undetected after 36 hours as a maximum wait time.

Urine testing – This method is often a more reliable form of testing as compared to some of the others and is a more common choice in Australia.
Urine testing will show a positive result in most cases if the test is within 48 hours of drug consumption, though diazepam and cannabis can often remain in the body for days or weeks after use.

Blood testing – A blood test will indicate of any substances traces in the body’s bloodstream, but recently research has indicated that testing the bloodstream is as effective as testing the saliva.

Hair testing – A hair follicle can retain a drugs presence for several months at times, though it takes about 5 days after consuming the substance for the results to show up in a hair follicle.

Though the above time frames are a rough guide to safe driving, illicit substances can remain present in the body for 90 days or more, so it is always recommended to not take that chance, the consequences are just not worth the risk involved.

Modern drugs such as synthetic cannabis (Spice), and flakka are also extremely grey areas, as the time that they remain in the human body is still unknown.

How do I pass a MDT test?

The only way to ensure that you will pass a MDT is to ensure that you are free from the influence of any drugs, seeing that even the numbers provided in this article are a rough guide, there is still no sure way to tell if an amount is still in your system.

Other factors such as hydration, body mass and the potency of the substance are also still all relevant to the time the drug will take to pass through your system.

What happens if I am charged?

The results of being convicted for driving under the influence of drugs is often a license suspension and a hefty fine, though being a first time offender can change the circumstances of the fine greatly, a full list of the potential penalties are best found on the offences and penalties section on the RMS website.

If you are in doubt of the offence or have questions, it is important to seek legal advice, talking to a professional can help you to understand the situation and what options are available.

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