According to a May 2026 Yahoo News report, a Sydney driver was pulled over for a routine roadside screening and returned a positive result for methamphetamine – despite insisting she had never used illicit drugs.
The only unusual factor? She had just finished a popular energy drink moments before being tested. While a second test returned a negative result, the experience highlights an area of drug testing that both workplaces and motorists should understand.
Why False Positives Can Occur
Roadside drug tests in NSW don’t identify exact chemical structures – instead they rely on immunoassays, which are quick chemical screening tests that use antibodies designed to bind to specific drug molecules (such as THC, methamphetamine, MDMA, and cocaine). These antibodies don’t identify exact substances – they look for similar chemical structures or “shapes.”
If a compound found in an energy drink, an over-the-counter medication, or a herbal supplement shares a similar structure to a target drug, the antibody may bind to it anyway. This phenomenon is known as cross-reactivity.
Research, including studies from the University of Sydney’s Lambert Initiative, has shown that roadside oral fluid devices can produce “false positive” results in approximately 5% to 10% of cases, depending on the device and substance.
Common Culprits in Everyday Products
While the specific energy drink in this case has not been formally examined in court, toxicology experts point to several everyday products that can interfere with preliminary screening tests:
- Cold and flu medications
Decongestants containing pseudoephedrine or phenylephrine can chemically mimic amphetamines on basic structural tests. - Hemp-based products
Some unrefined hemp seed oils or juices can contain minute, non-psychoactive traces of THC sufficient to trigger highly sensitive roadside swabs. - Herbal and wellness supplements
Certain botanical extracts and wellness products contain compounds that closely mirror the molecular structure of target analytes.
These products are legal — but under the right conditions, they may trigger a “not-negative” screening result.
The Legal “Limbo” for NSW Drivers
In NSW if you return a positive roadside reading, you face an immediate 24-hour driving ban. If the secondary test is also positive, you then enter a waiting period while a NATA-accredited laboratory analyses the sample using Gas or Liquid Chromatography–Tandem Mass Spectrometry (GC-MSMS or LC-MS/MS). If the laboratory confirms that no substance is present, the charges are dropped and no fines issued; however, for innocent drivers, this waiting period can create uncertainty.
Understanding the science behind drug testing, including cross-reactivity and false positives, is important not only from a roadside perspective, but also for workplace health and safety.
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