Drug driving tests are called into question after it's revealed a driver who took a PLACEBO tested positive for marijuana - and some heavy users test negative Researchers from The University of Sydney found inaccuracies with drug tests Roadside mobile saliva tests for THC gave inaccurate results 20 per cent of time Some drivers recorded fake positive tests including one who took a placeboBy Zoe Zaczek For Daily Mail Australia Published: 06:57 BST, 23 May 2019 | Updated: 08:31 BST, 23 May 2019 1 Viewcomments Drug driving tests have been called into question after a driver taking a placebo tested positive to cannabis. University of Sydney researchers found roadside mobile saliva tests for tetrahydrocannabinol (THC) were inaccurate more than 20 per cent of the time. In some instances, participants who were high on the drug tested negative while others who hadn't smoked in extended periods recorded false positives. The validity of drug driving tests have been called into question after a landmark case found a woman who tested positive to cannabis use had passively smoked the drug 'We had someone test positive for THC who was using a placebo,' lead researcher Professor Ian McGregor told ABC News. The research showed THC, which is responsible for cannabis' effect on the mind, is difficult to test, especially in large doses. 'The tests are particularly poor at detecting when people have a lot of THC in their system so they can be really stoned and getting a negative test,' Mr McGregor said. More alarmingly, some participants were handed false positive results. 'We found on occasion the tests gave a false positive when people have very low levels of THC and that is a concern for the carriage of justice, people are not impaired and they have not had cannabis for quite a long time,' Mr McGregor said. Research from The University of Sydney, which is yet to be released, found roadside mobile saliva tests for tetrahydrocannabinol gave inaccurate results more than 20 per cent of the time PENALTIES Drug driving and refusing to take a drug test are serious offences. As of 20 May 2019, if your roadside positive result is confirmed by the laboratory and it is a first-time offence, you may receive a $516 fine. Your licence would be subsequently suspended for three months. A second or subsequent offence means you would need to go to court. You may have your licence disqualified and receive a fine. Higher penalties apply if you are found guilty of driving under the influence. SOURCE: TRANSPORT FOR NSW The revelation comes after a landmark court case found a woman who tested positive to cannabis use had passively smoked the drug. Her charges were dropped last month with Magistrate David Heilpern saying scientists did not yet know everything about TCH, its rate and method of absorption. The NSW government introduced changes on May 20 to 'improve the certainty of penalties' for first-time offenders caught driving while under the influence of an illegal drug, as detected by mobile drug tests. A positive result confirmed by the laboratory could set back a first time offender $516 dollars and a three-month license suspension. 'We found on occasion the tests gave a false positive when people have very low levels of THC and that is a concern for the carriage of justice, people are not impaired and they have not had cannabis for quite a long time,' Professor Iain McGregor said THE DRUGS TESTED FOR AND HOW LONG ARE THEY IN YOUR SYSTEM Cannabis - Marijuana can be detected in urine for as long as 30 days after usage if the person being tested is a frequent user. For sporadic use, marijuana can still be detected about three days after usage. Ecstasy - Ecstasy or MDMA can be detected up to three days after first use. Methylamphetamine (speed/ice) - Depending on the amount ingested, ice can be detected as long as five days after use. Cocaine - Cocaine can return a positive result in urine tests up to two weeks after usage if the person being tested is a chronic user. For a less frequent user, cocaine can register in urine for two days after use. Source: The Mayo Clinic Read more: Share or comment on this article: All rights reserved for this news site dailymail and under his responsibility