Friday, 31 October 2014
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Roadside drug detection

On the back of the Think! drug drive campaign launch, The Engineer Online looks at an existing on-the-spot drug-detection technology and the barriers to its implementation.

The government is considering changing UK laws so that police officers can use roadside drug-detection devices to determine if motorists have taken narcotics.

The statement was made in a Radio 4 interview by transport secretary Lord Adonis, who was promoting the government’s £2.3m Think! advertising campaign to deter people from driving under the influence of illegal drugs.

Other countries such as Australia have tried tackling the issue over the last few years by equipping police officers with devices commonly known as drugalysers. These devices use a saliva sample from a driver to screen for illegal substances such as cannabis, cocaine and ecstasy. A result can be achieved in minutes.

Lord Adonis admitted roadside drug-testing devices would be ideal but it does not fit within current UK laws.

In the case of suspected drink driving, for example, a police officer can use a breathalyser to estimate if a driver has a blood alcohol level high enough to impair driving. Currently, police officers can use the Field Impairment Assessment (FIA) to ascertain if a motorist is under the influence of drugs.

The test is based on observation and does not involve a biological test. Motorists still under suspicion of using drugs following the FIA are arrested at the roadside and taken to a police station where a blood sample can be taken.

‘The law requires proving impairment,’ said Adrian Brophy, a spokesman for Concateno, a British maker of roadside drug-test devices, which are sold in countries such as Australia, Spain, Italy and Croatia, but not the UK.

‘The devices can be used there because there is not a need to prove impairment,’ he said. ‘The way those governments have approached the problem is to say “look, these drugs are illegal, we can’t necessarily prove impairment using these devices but we can prove someone’s taken it. Let’s take a zero-tolerance approach.”

Lord Adonis said that the government is currently reviewing the possibility of changing the laws. He proffered a new law could read that it is an offence to drive after taking illegal drugs as they are judged to cause impairment. In a report, the Department for Transport said that one fifth of drivers killed in road accidents ‘may have an impairing drug in their system’.

Brophy said Concateno is one of the companies consulting with the government on the issue.

‘In policy-making terms, it shouldn’t be something any government should rush into,’ he said. ‘The approach of… consulting and working on what the law is first before introducing these devices is actually pretty smart.’

The Concateno devices work using a type of biosensor known as an immunoassay. Dene Baldwin, group technical director of Concateno, said the technique uses antibodies to recognise a specific drug or group.

‘Those reagents are tagged with a coloured particle and they will react on a strip of paper depending on the drug concentration,’ he said. ‘What you’re left with then is something akin to a barcode, which goes into the reader and the reader will then analyse those areas and give a yes or no answer related to a particular concentration of drug.’

Baldwin said a drug must be in a concentration of 100ng/mm of a driver’s saliva sample to trigger a positive reading.

As reported in The Engineer in January, Concateno is working with Philips to improve their technology so that it is more sensitive, uses smaller sample quantities and provides faster results.

Baldwin said the devices, known as Magnotech, will be based on Philips’ magneto-resistance technology, which was developed through their work on magnetic hard drives of computers and DVDs.

‘They demonstrated that technology could be used to measure extremely low levels of analytes in less than 90 seconds,’ he said.

Baldwin said the devices will also be easier to use. Currently, he said, the saliva sample must be mixed with a buffer solution before putting it in the testing device. The Magnotech device does not require a buffer solution so it would be much easier for police officers to operate.

The devices will be commercially available at the end of this year, but Baldwin said to expect even more advanced and easier-to-use versions of the technology in years to come.

‘We are actively looking at ways of making the whole process easier to use,’ he said.

Siobhan Wagner

More information and video about Field Impairment Assessment can be found here: http://www.dft.gov.uk/think/drugdrive/testfordrugs.shtml


Readers' comments (1)

  • Amonsgt the drug treatment community these devices are notorious for giving false results.
    In addition a drug test does not detect impairment - only that a substance may be in the body. These tests are only screens and a confirmation via a lab would be needed.
    Ask other toxicologists within this group whether they believe that saliva is legally defensible.

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