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Deputy-Ombudsman Pajuoja cautions about unreliability of police?s quick drug test

Test often gives falsely gives positive result

22.11.2010

The quick drug test used by the police to check drivers of vehicles for drugs gives a positive result remarkably often, even if the test subject has not taken any. Especially the test for cannabis, cocaine and opiates gives incorrect positive results more than twice as many times as correct ones. The quick test reveals the use of amphetamine more reliably. However, even then nearly 10% of positive results are false.


Indeed, Deputy-Ombudsman Jussi Pajuoja considers it important that the police be aware of the limitations of the Drugwipe on-site test and do not accord too much weight to the test results when assessing the possibility of driving under the influence and considering a provisional driving ban.


Complaints led to study of the quick drug test's reliability more generally


The Deputy-Ombudsman has received several complaints about false positive results when the quick drug test was used. When investigating them, he received a report on the test from the National Institute for Health and Welfare (THL). This revealed the unreliability of the test. 


A test indicated that one of the complainants had used amphetamine. He had to spend the night in a police cell and had a provisional driving ban imposed on him. It later emerged that the person?s deviant behaviour was due to a brain tumour.


A second complainant?s test result indicated that he had used cannabis and amphetamine. This suspect had laboratory tests conducted at his own expense and they revealed no evidence of drug use. He had been subject to a provisional driving ban for 11 days. A month later, also the blood sample taken by the police confirmed that no driving under the influence had been involved.

A third complainant?s test result indicated that he had used cocaine and opiates. He was banned from driving for over a month before the forensic laboratory report on his blood sample cleared him of suspicion.


When assessing whether someone is driving under the influence, what value can be accorded a test when the positive result it gives is more likely to be wrong than right?


It is obvious that the result of a fast drug test can not be 100 per cent certain. Nevertheless, Deputy-Ombudsman Pajuoja finds it surprising that the test gives such unreliable results in relation to the use of cannabis, cocaine and opiates.


According to reports received by the Deputy-Ombudsman, the police have trusted the fast test. At least, there does not appear to be a clear picture among them of its unreliability. The probable explanation for this is that the overwhelming majority of persons caught had used amphetamine, which is more reliably revealed by the test.


Since the reliability of the test is poor when screening for the least common drugs, the Deputy-Ombudsman believes it is important that the police make also other observations of drivers, the way in which they drive and any driving errors. However, alternative explanations for what has been observed must always be taken into consideration. For example, all drivers make mistakes, and also an innocent person can behave nervously if the result of a fast test proves positive.


If the police place too much trust in the results of a fast test, suspicions of a crime along with the consequences, such as a driving ban, are often focused on the innocent. In the view of the Deputy-Ombudsman, this prompts the question of whether it is fair and whether the innocent should receive recompense at least in some cases. As such, it is very important to catch drivers who have taken drugs. The statutory limit for drugs in traffic is zero.


Unreliability of fast drug test to be made common knowledge among the police

Deputy-Ombudsman Jussi Pajuoja has sent a copy of his decision and of the National Institute for Health and Welfare?s report on the unreliability of the results of the fast drug test to the National Police Board to be forwarded to all police stations, the traffic police, the Police College and the Police Technical Centre as well as the headquarters of the Border Guard.


Additional information will be provided by Senior Legal Adviser Juha Haapamäki, tel. +358(0)9 4321.